AnyFreeSpec
Facilitates a “behavior-driven” style of development (BDD), in which tests
are nested inside text clauses denoted with the dash operator (-
).
AnyFreeSpec
is so named because unlike classes such as AnyWordSpec
, AnyFlatSpec
, and AnyFunSpec
,
it is enforces no structure on the text. You are free to compose text however you like. (A AnyFreeSpec
is like free-verse poetry as
opposed to a sonnet or haiku, which defines a structure for the text of the poem.)
Recommended Usage:
Because it gives absolute freedom (and no guidance) on how specification text should be written, AnyFreeSpec is a good choice for teams experienced
with BDD and able to agree on how to structure the specification text.
|
Here's an example AnyFreeSpec
:
package org.scalatest.examples.freespec import org.scalatest.freespec.AnyFreeSpec class SetSpec extends AnyFreeSpec { "A Set" - { "when empty" - { "should have size 0" in { assert(Set.empty.size === 0) } "should produce NoSuchElementException when head is invoked" in { assertThrows[NoSuchElementException] { Set.empty.head } } } } }
In a AnyFreeSpec
you write a test with a string followed by in
and the body of the
test in curly braces, like this:
"should have size 0" in { // ... }
You can nest a test inside any number of description clauses, which you write with a string followed by a dash character and a block, like this:
"A Set" - { // ... }
You can nest description clauses as deeply as you want. Because the description clause is denoted with an operator, not
a word like should
, you are free to structure the text however you wish. Here's an example:
import org.scalatest.freespec.AnyFreeSpec class StackSpec extends AnyFreeSpec { "A Stack" - { "whenever it is empty" - { "certainly ought to" - { "be empty" in { // ... } "complain on peek" in { // ... } "complain on pop" in { // ... } } } "but when full, by contrast, must" - { "be full" in { // ... } "complain on push" in { // ... } } } }
Running the above StackSpec
in the interpreter would yield:
scala> org.scalatest.run(new StackSpec)
StackSpec:
A Stack
whenever it is empty
certainly ought to
- be empty
- complain on peek
- complain on pop
but when full, by contrast, must
- be full
- complain on push
A AnyFreeSpec
can also be used to write a specification-style test in languages other than English. For
example:
import org.scalatest.freespec.AnyFreeSpec class ComputerRoomRulesSpec extends AnyFreeSpec { "Achtung!" - { "Alle touristen und non-technischen lookenpeepers!" - { "Das machine is nicht fuer fingerpoken und mittengrabben." in { // ... } "Is easy" - { "schnappen der springenwerk" in { // ... } "blowenfusen" in { // ... } "und poppencorken mit spitzen sparken." in { // ... } } "Das machine is diggen by experten only." in { // ... } "Is nicht fuer gerwerken by das dummkopfen." in { // ... } "Das rubbernecken sightseeren keepen das cottenpicken hands in das pockets." in { // ... } "Relaxen und watchen das blinkenlights." in { // ... } } } }
Running the above ComputerRoomRulesSpec
in the interpreter would yield:
scala> org.scalatest.run(new ComputerRoomRulesSpec)
ComputerRoomRulesSpec:
Achtung!
Alle touristen und non-technischen lookenpeepers!
- Das machine is nicht fuer fingerpoken und mittengrabben.
Is easy
- schnappen der springenwerk
- blowenfusen
- und poppencorken mit spitzen sparken.
- Das machine is diggen by experten only.
- Is nicht fuer gerwerken by das dummkopfen.
- Das rubbernecken sightseeren keepen das cottenpicken hands in das pockets.
- Relaxen und watchen das blinkenlights.
A AnyFreeSpec
's lifecycle has two phases: the registration phase and the
ready phase. It starts in registration phase and enters ready phase the first time
run
is called on it. It then remains in ready phase for the remainder of its lifetime.
Tests can only be registered while the AnyFreeSpec
is
in its registration phase. Any attempt to register a test after the AnyFreeSpec
has
entered its ready phase, i.e., after run
has been invoked on the AnyFreeSpec
,
will be met with a thrown TestRegistrationClosedException
. The recommended style
of using AnyFreeSpec
is to register tests during object construction as is done in all
the examples shown here. If you keep to the recommended style, you should never see a
TestRegistrationClosedException
.
To support the common use case of temporarily disabling a test, with the
good intention of resurrecting the test at a later time, AnyFreeSpec
adds a method
ignore
to strings that can be used instead of in
to register a test. For example, to temporarily
disable the test with the name "A Stack should pop values in last-in-first-out order"
, just
change “in
” into “ignore
,” like this:
package org.scalatest.examples.freespec.ignore import org.scalatest.freespec.AnyFreeSpec class SetSpec extends AnyFreeSpec { "A Set" - { "when empty" - { "should have size 0" ignore { assert(Set.empty.size === 0) } "should produce NoSuchElementException when head is invoked" in { assertThrows[NoSuchElementException] { Set.empty.head } } } } }
If you run this version of SetSpec
with:
scala> org.scalatest.run(new SetSpec)
It will run only the second test and report that the first test was ignored:
A Set when empty - should have size 0 !!! IGNORED !!! - should produce NoSuchElementException when head is invoked
If you wish to temporarily ignore an entire suite of tests, you can (on the JVM, not Scala.js) annotate the test class with @Ignore
, like this:
package org.scalatest.examples.freespec.ignoreall import org.scalatest.freespec.AnyFreeSpec import org.scalatest.Ignore @Ignore class SetSpec extends AnyFreeSpec { "A Set" - { "when empty" - { "should have size 0" in { assert(Set.empty.size === 0) } "should produce NoSuchElementException when head is invoked" in { assertThrows[NoSuchElementException] { Set.empty.head } } } } }
When you mark a test class with a tag annotation, ScalaTest will mark each test defined in that class with that tag.
Thus, marking the SetSpec
in the above example with the @Ignore
tag annotation means that both tests
in the class will be ignored. If you run the above SetSpec
in the Scala interpreter, you'll see:
scala> org.scalatest.run(new SetSpec) SetSpec: A Set when empty - should have size 0 !!! IGNORED !!! - should produce NoSuchElementException when head is invoked !!! IGNORED !!!
Note that marking a test class as ignored won't prevent it from being discovered by ScalaTest. Ignored classes
will be discovered and run, and all their tests will be reported as ignored. This is intended to keep the ignored
class visible, to encourage the developers to eventually fix and “un-ignore” it. If you want to
prevent a class from being discovered at all (on the JVM, not Scala.js), use the DoNotDiscover
annotation instead.
One of the parameters to AnyFreeSpec
's run
method is a Reporter
, which
will collect and report information about the running suite of tests.
Information about suites and tests that were run, whether tests succeeded or failed,
and tests that were ignored will be passed to the Reporter
as the suite runs.
Most often the reporting done by default by AnyFreeSpec
's methods will be sufficient, but
occasionally you may wish to provide custom information to the Reporter
from a test.
For this purpose, an Informer
that will forward information to the current Reporter
is provided via the info
parameterless method.
You can pass the extra information to the Informer
via its apply
method.
The Informer
will then pass the information to the Reporter
via an InfoProvided
event.
One use case for the Informer
is to pass more information about a specification to the reporter. For example,
the GivenWhenThen
trait provides methods that use the implicit info
provided by AnyFreeSpec
to pass such information to the reporter. Here's an example:
package org.scalatest.examples.freespec.info import collection.mutable import org.scalatest._ class SetSpec extends freespec.AnyFreeSpec with GivenWhenThen { "A mutable Set" - { "should allow an element to be added" in { Given("an empty mutable Set") val set = mutable.Set.empty[String] When("an element is added") set += "clarity" Then("the Set should have size 1") assert(set.size === 1) And("the Set should contain the added element") assert(set.contains("clarity")) info("That's all folks!") } } }
If you run this AnyFreeSpec
from the interpreter, you will see the following output:
scala> org.scalatest.run(new SetSpec)
A mutable Set
- should allow an element to be added
+ Given an empty mutable Set
+ When an element is added
+ Then the Set should have size 1
+ And the Set should contain the added element
+ That's all folks!
AnyFreeSpec
also provides a markup
method that returns a Documenter
, which allows you to send
to the Reporter
text formatted in Markdown syntax.
You can pass the extra information to the Documenter
via its apply
method.
The Documenter
will then pass the information to the Reporter
via an MarkupProvided
event.
Here's an example AnyFreeSpec
that uses markup
:
package org.scalatest.examples.freespec.markup import collection.mutable import org.scalatest._ class SetSpec extends freespec.AnyFreeSpec with GivenWhenThen { markup { """ Mutable Set ----------- A set is a collection that contains no duplicate elements. To implement a concrete mutable set, you need to provide implementations of the following methods: def contains(elem: A): Boolean def iterator: Iterator[A] def += (elem: A): this.type def -= (elem: A): this.type If you wish that methods like `take`, `drop`, `filter` return the same kind of set, you should also override: def empty: This It is also good idea to override methods `foreach` and `size` for efficiency. """ } "A mutable Set" - { "should allow an element to be added" in { Given("an empty mutable Set") val set = mutable.Set.empty[String] When("an element is added") set += "clarity" Then("the Set should have size 1") assert(set.size === 1) And("the Set should contain the added element") assert(set.contains("clarity")) markup("This test finished with a **bold** statement!") } } }
Although all of ScalaTest's built-in reporters will display the markup text in some form,
the HTML reporter will format the markup information into HTML. Thus, the main purpose of markup
is to
add nicely formatted text to HTML reports. Here's what the above SetSpec
would look like in the HTML reporter:
ScalaTest records text passed to info
and markup
during tests, and sends the recorded text in the recordedEvents
field of
test completion events like TestSucceeded
and TestFailed
. This allows string reporters (like the standard out reporter) to show
info
and markup
text after the test name in a color determined by the outcome of the test. For example, if the test fails, string
reporters will show the info
and markup
text in red. If a test succeeds, string reporters will show the info
and markup
text in green. While this approach helps the readability of reports, it means that you can't use info
to get status
updates from long running tests.
To get immediate (i.e., non-recorded) notifications from tests, you can use note
(a Notifier
) and alert
(an Alerter
). Here's an example showing the differences:
package org.scalatest.examples.freespec.note import collection.mutable import org.scalatest._ class SetSpec extends freespec.AnyFreeSpec { "A mutable Set" - { "should allow an element to be added" in { info("info is recorded") markup("markup is *also* recorded") note("notes are sent immediately") alert("alerts are also sent immediately") val set = mutable.Set.empty[String] set += "clarity" assert(set.size === 1) assert(set.contains("clarity")) } } }
scala> org.scalatest.run(new SetSpec) SetSpec: A mutable Set + notes are sent immediately + alerts are also sent immediately - should allow an element to be added + info is recorded + markup is *also* recorded
Another example is slowpoke notifications.
If you find a test is taking a long time to complete, but you're not sure which test, you can enable
slowpoke notifications. ScalaTest will use an Alerter
to fire an event whenever a test has been running
longer than a specified amount of time.
In summary, use info
and markup
for text that should form part of the specification output. Use
note
and alert
to send status notifications. (Because the HTML reporter is intended to produce a
readable, printable specification, info
and markup
text will appear in the HTML report, but
note
and alert
text will not.)
A pending test is one that has been given a name but is not yet implemented. The purpose of pending tests is to facilitate a style of testing in which documentation of behavior is sketched out before tests are written to verify that behavior (and often, before the behavior of the system being tested is itself implemented). Such sketches form a kind of specification of what tests and functionality to implement later.
To support this style of testing, a test can be given a name that specifies one
bit of behavior required by the system being tested. The test can also include some code that
sends more information about the behavior to the reporter when the tests run. At the end of the test,
it can call method pending
, which will cause it to complete abruptly with TestPendingException
.
Because tests in ScalaTest can be designated as pending with TestPendingException
, both the test name and any information
sent to the reporter when running the test can appear in the report of a test run. (In other words,
the code of a pending test is executed just like any other test.) However, because the test completes abruptly
with TestPendingException
, the test will be reported as pending, to indicate
the actual test, and possibly the functionality it is intended to test, has not yet been implemented.
You can mark tests as pending in a AnyFreeSpec
like this:
package org.scalatest.examples.freespec.pending import org.scalatest._ class SetSpec extends freespec.AnyFreeSpec { "A Set" - { "when empty" - { "should have size 0" in (pending) "should produce NoSuchElementException when head is invoked" in { assertThrows[NoSuchElementException] { Set.empty.head } } } } }
If you run this version of SetSpec
with:
scala> org.scalatest.run(new SetSpec)
It will run both tests but report that should have size 0
is pending. You'll see:
A Set when empty - should have size 0 (pending) - should produce NoSuchElementException when head is invoked
One difference between an ignored test and a pending one is that an ignored test is intended to be used during a significant refactorings of the code under test, when tests break and you don't want to spend the time to fix all of them immediately. You can mark some of those broken tests as ignored temporarily, so that you can focus the red bar on just failing tests you actually want to fix immediately. Later you can go back and fix the ignored tests. In other words, by ignoring some failing tests temporarily, you can more easily notice failed tests that you actually want to fix. By contrast, a pending test is intended to be used before a test and/or the code under test is written. Pending indicates you've decided to write a test for a bit of behavior, but either you haven't written the test yet, or have only written part of it, or perhaps you've written the test but don't want to implement the behavior it tests until after you've implemented a different bit of behavior you realized you need first. Thus ignored tests are designed to facilitate refactoring of existing code whereas pending tests are designed to facilitate the creation of new code.
One other difference between ignored and pending tests is that ignored tests are implemented as a test tag that is
excluded by default. Thus an ignored test is never executed. By contrast, a pending test is implemented as a
test that throws TestPendingException
(which is what calling the pending
method does). Thus
the body of pending tests are executed up until they throw TestPendingException
. The reason for this difference
is that it enables your unfinished test to send InfoProvided
messages to the reporter before it completes
abruptly with TestPendingException
, as shown in the previous example on Informer
s
that used the GivenWhenThen
trait. For example, the following snippet in a AnyFreeSpec
:
"The Scala language" - { "should add correctly" in { Given("two integers") When("they are added") Then("the result is the sum of the two numbers") pending } // ...
Would yield the following output when run in the interpreter:
The Scala language - should add correctly (pending) + Given two integers + When they are added + Then the result is the sum of the two numbers
A AnyFreeSpec
's tests may be classified into groups by tagging them with string names.
As with any suite, when executing a AnyFreeSpec
, groups of tests can
optionally be included and/or excluded. To tag a AnyFreeSpec
's tests,
you pass objects that extend class org.scalatest.Tag
to methods
that register tests. Class Tag
takes one parameter, a string name. If you have
created tag annotation interfaces as described in the Tag
documentation, then you
will probably want to use tag names on your test functions that match. To do so, simply
pass the fully qualified names of the tag interfaces to the Tag
constructor. For example, if you've
defined a tag annotation interface with fully qualified name,
com.mycompany.tags.DbTest
, then you could
create a matching tag for AnyFreeSpec
s like this:
import org.scalatest.Tag object DbTest extends Tag("com.mycompany.tags.DbTest")
Given these definitions, you could tag AnyFreeSpec
tests like this:
package org.scalatest.examples.freespec.tagging import org.scalatest.Tag object DbTest extends Tag("com.mycompany.tags.DbTest") import org.scalatest.freespec.AnyFreeSpec import org.scalatest.tagobjects.Slow class SetSpec extends AnyFreeSpec { "A Set" - { "when empty" - { "should have size 0" taggedAs(Slow) in { assert(Set.empty.size === 0) } "should produce NoSuchElementException when head is invoked" taggedAs(Slow, DbTest) in { assertThrows[NoSuchElementException] { Set.empty.head } } } } }
This code marks both tests with the org.scalatest.tags.Slow
tag,
and the second test with the com.mycompany.tags.DbTest
tag.
The run
method takes a Filter
, whose constructor takes an optional
Set[String]
called tagsToInclude
and a Set[String]
called
tagsToExclude
. If tagsToInclude
is None
, all tests will be run
except those those belonging to tags listed in the
tagsToExclude
Set
. If tagsToInclude
is defined, only tests
belonging to tags mentioned in the tagsToInclude
set, and not mentioned in tagsToExclude
,
will be run.
It is recommended, though not required, that you create a corresponding tag annotation when you
create a Tag
object. A tag annotation (on the JVM, not Scala.js) allows you to tag all the tests of a AnyFreeSpec
in
one stroke by annotating the class. For more information and examples, see the
documentation for class Tag
. On Scala.js, to tag all tests of a suite, you'll need to
tag each test individually at the test site.
== Shared fixtures ==
A test fixture is composed of the objects and other artifacts (files, sockets, database connections, etc.) tests use to do their work. When multiple tests need to work with the same fixtures, it is important to try and avoid duplicating the fixture code across those tests. The more code duplication you have in your tests, the greater drag the tests will have on refactoring the actual production code.
ScalaTest recommends three techniques to eliminate such code duplication:
-
Refactor using Scala
-
Override
withFixture
-
Mix in a before-and-after trait
Each technique is geared towards helping you reduce code duplication without introducing
instance var
s, shared mutable objects, or other dependencies between tests. Eliminating shared
mutable state across tests will make your test code easier to reason about and more amenable for parallel
test execution.
The following sections describe these techniques, including explaining the recommended usage for each. But first, here's a table summarizing the options:
Refactor using Scala when different tests need different fixtures. | |
get-fixture methods | The extract method refactor helps you create a fresh instances of mutable fixture objects in each test that needs them, but doesn't help you clean them up when you're done. |
fixture-context objects | By placing fixture methods and fields into traits, you can easily give each test just the newly created fixtures it needs by mixing together traits. Use this technique when you need different combinations of mutable fixture objects in different tests, and don't need to clean up after. |
loan-fixture methods | Factor out dupicate code with the loan pattern when different tests need different fixtures that must be cleaned up afterwards. |
Override withFixture when most or all tests need the same fixture.
|
|
withFixture(NoArgTest)
|
The recommended default approach when most or all tests need the same fixture treatment. This general technique allows you, for example, to perform side effects at the beginning and end of all or most tests, transform the outcome of tests, retry tests, make decisions based on test names, tags, or other test data. Use this technique unless:
|
withFixture(OneArgTest)
|
Use when you want to pass the same fixture object or objects as a parameter into all or most tests. |
Mix in a before-and-after trait when you want an aborted suite, not a failed test, if the fixture code fails. | |
BeforeAndAfter
|
Use this boilerplate-buster when you need to perform the same side-effects before and/or after tests, rather than at the beginning or end of tests. |
BeforeAndAfterEach
|
Use when you want to stack traits that perform the same side-effects before and/or after tests, rather than at the beginning or end of tests. |
==== Calling get-fixture methods ====
If you need to create the same mutable fixture objects in multiple tests, and don't need to clean them up after using them, the simplest approach is to write one or more get-fixture methods. A get-fixture method returns a new instance of a needed fixture object (or an holder object containing multiple fixture objects) each time it is called. You can call a get-fixture method at the beginning of each test that needs the fixture, storing the returned object or objects in local variables. Here's an example:
package org.scalatest.examples.freespec.getfixture import org.scalatest.freespec.AnyFreeSpec import collection.mutable.ListBuffer class ExampleSpec extends AnyFreeSpec { class Fixture { val builder = new StringBuilder("ScalaTest is ") val buffer = new ListBuffer[String] } def fixture = new Fixture "Testing" - { "should be easy" in { val f = fixture f.builder.append("easy!") assert(f.builder.toString === "ScalaTest is easy!") assert(f.buffer.isEmpty) f.buffer += "sweet" } "should be fun" in { val f = fixture f.builder.append("fun!") assert(f.builder.toString === "ScalaTest is fun!") assert(f.buffer.isEmpty) } } }
The “f.
” in front of each use of a fixture object provides a visual indication of which objects
are part of the fixture, but if you prefer, you can import the the members with “import f._
” and use the names directly.
If you need to configure fixture objects differently in different tests, you can pass configuration into the get-fixture method. For example, if you could pass in an initial value for a mutable fixture object as a parameter to the get-fixture method.
==== Instantiating fixture-context objects ====
An alternate technique that is especially useful when different tests need different combinations of fixture objects is to define the fixture objects as instance variables of fixture-context objects whose instantiation forms the body of tests. Like get-fixture methods, fixture-context objects are only appropriate if you don't need to clean up the fixtures after using them.
To use this technique, you define instance variables intialized with fixture objects in traits and/or classes, then in each test instantiate an object that contains just the fixture objects needed by the test. Traits allow you to mix together just the fixture objects needed by each test, whereas classes allow you to pass data in via a constructor to configure the fixture objects. Here's an example in which fixture objects are partitioned into two traits and each test just mixes together the traits it needs:
package org.scalatest.examples.freespec.fixturecontext import collection.mutable.ListBuffer import org.scalatest.freespec.AnyFreeSpec class ExampleSpec extends AnyFreeSpec { trait Builder { val builder = new StringBuilder("ScalaTest is ") } trait Buffer { val buffer = ListBuffer("ScalaTest", "is") } "Testing" - { // This test needs the StringBuilder fixture "should be productive" in new Builder { builder.append("productive!") assert(builder.toString === "ScalaTest is productive!") } } "Test code" - { // This test needs the ListBuffer[String] fixture "should be readable" in new Buffer { buffer += ("readable!") assert(buffer === List("ScalaTest", "is", "readable!")) } // This test needs both the StringBuilder and ListBuffer "should be clear and concise" in new Builder with Buffer { builder.append("clear!") buffer += ("concise!") assert(builder.toString === "ScalaTest is clear!") assert(buffer === List("ScalaTest", "is", "concise!")) } } }
==== Overriding withFixture(NoArgTest)
====
Although the get-fixture method and fixture-context object approaches take care of setting up a fixture at the beginning of each
test, they don't address the problem of cleaning up a fixture at the end of the test. If you just need to perform a side-effect at the beginning or end of
a test, and don't need to actually pass any fixture objects into the test, you can override withFixture(NoArgTest)
, one of ScalaTest's
lifecycle methods defined in trait Suite
.
Trait Suite
's implementation of runTest
passes a no-arg test function to withFixture(NoArgTest)
. It is withFixture
's
responsibility to invoke that test function. Suite
's implementation of withFixture
simply
invokes the function, like this:
// Default implementation in trait Suite protected def withFixture(test: NoArgTest) = { test() }
You can, therefore, override withFixture
to perform setup before and/or cleanup after invoking the test function. If
you have cleanup to perform, you should invoke the test function inside a try
block and perform the cleanup in
a finally
clause, in case an exception propagates back through withFixture
. (If a test fails because of an exception,
the test function invoked by withFixture will result in a <code>Failed</code> wrapping the exception. Nevertheless,
best practice is to perform cleanup in a finally clause just in case an exception occurs.)
The withFixture
method is designed to be stacked, and to enable this, you should always call the super
implementation
of withFixture
, and let it invoke the test function rather than invoking the test function directly. In other words, instead of writing
“test()
”, you should write “super.withFixture(test)
”, like this:
// Your implementation override def withFixture(test: NoArgTest) = { // Perform setup try super.withFixture(test) // Invoke the test function finally { // Perform cleanup } }
Here's an example in which withFixture(NoArgTest)
is used to take a snapshot of the working directory if a test fails, and
send that information to the reporter:
package org.scalatest.examples.freespec.noargtest import java.io.File import org.scalatest._ class ExampleSpec extends freespec.AnyFreeSpec { override def withFixture(test: NoArgTest) = { super.withFixture(test) match { case failed: Failed => val currDir = new File(".") val fileNames = currDir.list() info("Dir snapshot: " + fileNames.mkString(", ")) failed case other => other } } "This test" - { "should succeed" in { assert(1 + 1 === 2) } "should fail" in { assert(1 + 1 === 3) } } }
Running this version of ExampleSuite
in the interpreter in a directory with two files, hello.txt
and world.txt
would give the following output:
scala> org.scalatest.run(new ExampleSuite) ExampleSuite: This test - should succeed - should fail *** FAILED *** 2 did not equal 3 (:33) + Dir snapshot: hello.txt, world.txt
Note that the NoArgTest
passed to withFixture
, in addition to
an apply
method that executes the test, also includes the test name and the config
map passed to runTest
. Thus you can also use the test name and configuration objects in your withFixture
implementation.
==== Calling loan-fixture methods ====
If you need to both pass a fixture object into a test and perform cleanup at the end of the test, you'll need to use the loan pattern. If different tests need different fixtures that require cleanup, you can implement the loan pattern directly by writing loan-fixture methods. A loan-fixture method takes a function whose body forms part or all of a test's code. It creates a fixture, passes it to the test code by invoking the function, then cleans up the fixture after the function returns.
The following example shows three tests that use two fixtures, a database and a file. Both require cleanup after, so each is provided via a
loan-fixture method. (In this example, the database is simulated with a StringBuffer
.)
package org.scalatest.examples.freespec.loanfixture import java.util.concurrent.ConcurrentHashMap object DbServer { // Simulating a database server type Db = StringBuffer private val databases = new ConcurrentHashMap[String, Db] def createDb(name: String): Db = { val db = new StringBuffer databases.put(name, db) db } def removeDb(name: String) { databases.remove(name) } } import org.scalatest.freespec.AnyFreeSpec import DbServer._ import java.util.UUID.randomUUID import java.io._ class ExampleSpec extends AnyFreeSpec { def withDatabase(testCode: Db => Any) { val dbName = randomUUID.toString val db = createDb(dbName) // create the fixture try { db.append("ScalaTest is ") // perform setup testCode(db) // "loan" the fixture to the test } finally removeDb(dbName) // clean up the fixture } def withFile(testCode: (File, FileWriter) => Any) { val file = File.createTempFile("hello", "world") // create the fixture val writer = new FileWriter(file) try { writer.write("ScalaTest is ") // set up the fixture testCode(file, writer) // "loan" the fixture to the test } finally writer.close() // clean up the fixture } "Testing" - { // This test needs the file fixture "should be productive" in withFile { (file, writer) => writer.write("productive!") writer.flush() assert(file.length === 24) } } "Test code" - { // This test needs the database fixture "should be readable" in withDatabase { db => db.append("readable!") assert(db.toString === "ScalaTest is readable!") } // This test needs both the file and the database "should be clear and concise" in withDatabase { db => withFile { (file, writer) => // loan-fixture methods compose db.append("clear!") writer.write("concise!") writer.flush() assert(db.toString === "ScalaTest is clear!") assert(file.length === 21) } } } }
As demonstrated by the last test, loan-fixture methods compose. Not only do loan-fixture methods allow you to give each test the fixture it needs, they allow you to give a test multiple fixtures and clean everything up afterwards.
Also demonstrated in this example is the technique of giving each test its own "fixture sandbox" to play in. When your fixtures involve external side-effects, like creating files or databases, it is a good idea to give each file or database a unique name as is done in this example. This keeps tests completely isolated, allowing you to run them in parallel if desired.
==== Overriding withFixture(OneArgTest)
====
If all or most tests need the same fixture, you can avoid some of the boilerplate of the loan-fixture method approach by using a FixtureAnyFreeSpec
and overriding withFixture(OneArgTest)
.
Each test in a FixtureAnyFreeSpec
takes a fixture as a parameter, allowing you to pass the fixture into
the test. You must indicate the type of the fixture parameter by specifying FixtureParam
, and implement a
withFixture
method that takes a OneArgTest
. This withFixture
method is responsible for
invoking the one-arg test function, so you can perform fixture set up before, and clean up after, invoking and passing
the fixture into the test function.
To enable the stacking of traits that define withFixture(NoArgTest)
, it is a good idea to let
withFixture(NoArgTest)
invoke the test function instead of invoking the test
function directly. To do so, you'll need to convert the OneArgTest
to a NoArgTest
. You can do that by passing
the fixture object to the toNoArgTest
method of OneArgTest
. In other words, instead of
writing “test(theFixture)
”, you'd delegate responsibility for
invoking the test function to the withFixture(NoArgTest)
method of the same instance by writing:
withFixture(test.toNoArgTest(theFixture))
Here's a complete example:
package org.scalatest.examples.freespec.oneargtest import org.scalatest._ import java.io._ class ExampleSpec extends freespec.FixtureAnyFreeSpec { case class FixtureParam(file: File, writer: FileWriter) def withFixture(test: OneArgTest) = { // create the fixture val file = File.createTempFile("hello", "world") val writer = new FileWriter(file) val theFixture = FixtureParam(file, writer) try { writer.write("ScalaTest is ") // set up the fixture withFixture(test.toNoArgTest(theFixture)) // "loan" the fixture to the test } finally writer.close() // clean up the fixture } "Testing" - { "should be easy" in { f => f.writer.write("easy!") f.writer.flush() assert(f.file.length === 18) } "should be fun" in { f => f.writer.write("fun!") f.writer.flush() assert(f.file.length === 17) } } }
In this example, the tests actually required two fixture objects, a File
and a FileWriter
. In such situations you can
simply define the FixtureParam
type to be a tuple containing the objects, or as is done in this example, a case class containing
the objects. For more information on the withFixture(OneArgTest)
technique, see the documentation for FixtureAnyFreeSpec
.
==== Mixing in BeforeAndAfter
====
In all the shared fixture examples shown so far, the activities of creating, setting up, and cleaning up the fixture objects have been
performed during the test. This means that if an exception occurs during any of these activities, it will be reported as a test failure.
Sometimes, however, you may want setup to happen before the test starts, and cleanup after the test has completed, so that if an
exception occurs during setup or cleanup, the entire suite aborts and no more tests are attempted. The simplest way to accomplish this in ScalaTest is
to mix in trait BeforeAndAfter
. With this trait you can denote a bit of code to run before each test
with before
and/or after each test each test with after
, like this:
package org.scalatest.examples.freespec.beforeandafter import org.scalatest.freespec.AnyFreeSpec import org.scalatest.BeforeAndAfter import collection.mutable.ListBuffer class ExampleSpec extends AnyFreeSpec with BeforeAndAfter { val builder = new StringBuilder val buffer = new ListBuffer[String] before { builder.append("ScalaTest is ") } after { builder.clear() buffer.clear() } "Testing" - { "should be easy" in { builder.append("easy!") assert(builder.toString === "ScalaTest is easy!") assert(buffer.isEmpty) buffer += "sweet" } "should be fun" in { builder.append("fun!") assert(builder.toString === "ScalaTest is fun!") assert(buffer.isEmpty) } } }
Note that the only way before
and after
code can communicate with test code is via some side-effecting mechanism, commonly by
reassigning instance var
s or by changing the state of mutable objects held from instance val
s (as in this example). If using
instance var
s or mutable objects held from instance val
s you wouldn't be able to run tests in parallel in the same instance
of the test class (on the JVM, not Scala.js) unless you synchronized access to the shared, mutable state. This is why ScalaTest's ParallelTestExecution
trait extends
OneInstancePerTest
. By running each test in its own instance of the class, each test has its own copy of the instance variables, so you
don't need to synchronize. If you mixed ParallelTestExecution
into the ExampleSuite
above, the tests would run in parallel just fine
without any synchronization needed on the mutable StringBuilder
and ListBuffer[String]
objects.
Although BeforeAndAfter
provides a minimal-boilerplate way to execute code before and after tests, it isn't designed to enable stackable
traits, because the order of execution would be non-obvious. If you want to factor out before and after code that is common to multiple test suites, you
should use trait BeforeAndAfterEach
instead, as shown later in the next section,
composing fixtures by stacking traits.
== Composing fixtures by stacking traits ==
In larger projects, teams often end up with several different fixtures that test classes need in different combinations,
and possibly initialized (and cleaned up) in different orders. A good way to accomplish this in ScalaTest is to factor the individual
fixtures into traits that can be composed using the stackable trait pattern. This can be done, for example, by placing
withFixture
methods in several traits, each of which call super.withFixture
. Here's an example in
which the StringBuilder
and ListBuffer[String]
fixtures used in the previous examples have been
factored out into two stackable fixture traits named Builder
and Buffer
:
package org.scalatest.examples.freespec.composingwithfixture import org.scalatest._ import collection.mutable.ListBuffer trait Builder extends TestSuiteMixin { this: TestSuite => val builder = new StringBuilder abstract override def withFixture(test: NoArgTest) = { builder.append("ScalaTest is ") try super.withFixture(test) // To be stackable, must call super.withFixture finally builder.clear() } } trait Buffer extends TestSuiteMixin { this: TestSuite => val buffer = new ListBuffer[String] abstract override def withFixture(test: NoArgTest) = { try super.withFixture(test) // To be stackable, must call super.withFixture finally buffer.clear() } } class ExampleSpec extends freespec.AnyFreeSpec with Builder with Buffer { "Testing" - { "should be easy" in { builder.append("easy!") assert(builder.toString === "ScalaTest is easy!") assert(buffer.isEmpty) buffer += "sweet" } "should be fun" in { builder.append("fun!") assert(builder.toString === "ScalaTest is fun!") assert(buffer.isEmpty) buffer += "clear" } } }
By mixing in both the Builder
and Buffer
traits, ExampleSuite
gets both fixtures, which will be
initialized before each test and cleaned up after. The order the traits are mixed together determines the order of execution.
In this case, Builder
is “super” to Buffer
. If you wanted Buffer
to be “super”
to Builder
, you need only switch the order you mix them together, like this:
class Example2Spec extends freespec.AnyFreeSpec with Buffer with Builder
And if you only need one fixture you mix in only that trait:
class Example3Spec extends freespec.AnyFreeSpec with Builder
Another way to create stackable fixture traits is by extending the BeforeAndAfterEach
and/or BeforeAndAfterAll
traits.
BeforeAndAfterEach
has a beforeEach
method that will be run before each test (like JUnit's setUp
),
and an afterEach
method that will be run after (like JUnit's tearDown
).
Similarly, BeforeAndAfterAll
has a beforeAll
method that will be run before all tests,
and an afterAll
method that will be run after all tests. Here's what the previously shown example would look like if it
were rewritten to use the BeforeAndAfterEach
methods instead of withFixture
:
package org.scalatest.examples.freespec.composingbeforeandaftereach import org.scalatest._ import org.scalatest.BeforeAndAfterEach import collection.mutable.ListBuffer trait Builder extends BeforeAndAfterEach { this: Suite => val builder = new StringBuilder override def beforeEach() { builder.append("ScalaTest is ") super.beforeEach() // To be stackable, must call super.beforeEach } override def afterEach() { try super.afterEach() // To be stackable, must call super.afterEach finally builder.clear() } } trait Buffer extends BeforeAndAfterEach { this: Suite => val buffer = new ListBuffer[String] override def afterEach() { try super.afterEach() // To be stackable, must call super.afterEach finally buffer.clear() } } class ExampleSpec extends freespec.AnyFreeSpec with Builder with Buffer { "Testing" - { "should be easy" in { builder.append("easy!") assert(builder.toString === "ScalaTest is easy!") assert(buffer.isEmpty) buffer += "sweet" } "should be fun" in { builder.append("fun!") assert(builder.toString === "ScalaTest is fun!") assert(buffer.isEmpty) buffer += "clear" } } }
To get the same ordering as withFixture
, place your super.beforeEach
call at the end of each
beforeEach
method, and the super.afterEach
call at the beginning of each afterEach
method, as shown in the previous example. It is a good idea to invoke super.afterEach
in a try
block and perform cleanup in a finally
clause, as shown in the previous example, because this ensures the
cleanup code is performed even if super.afterEach
throws an exception.
The difference between stacking traits that extend BeforeAndAfterEach
versus traits that implement withFixture
is
that setup and cleanup code happens before and after the test in BeforeAndAfterEach
, but at the beginning and
end of the test in withFixture
. Thus if a withFixture
method completes abruptly with an exception, it is
considered a failed test. By contrast, if any of the beforeEach
or afterEach
methods of BeforeAndAfterEach
complete abruptly, it is considered an aborted suite, which will result in a SuiteAborted
event.
Sometimes you may want to run the same test code on different fixture objects. In other words, you may want to write tests that are "shared"
by different fixture objects. To accomplish this in a AnyFreeSpec
, you first place shared tests in behavior functions.
These behavior functions will be invoked during the construction phase of any AnyFreeSpec
that uses them, so that the tests they
contain will be registered as tests in that AnyFreeSpec
. For example, given this stack class:
import scala.collection.mutable.ListBuffer class Stack[T] { val MAX = 10 private val buf = new ListBuffer[T] def push(o: T) { if (!full) buf.prepend(o) else throw new IllegalStateException("can't push onto a full stack") } def pop(): T = { if (!empty) buf.remove(0) else throw new IllegalStateException("can't pop an empty stack") } def peek: T = { if (!empty) buf(0) else throw new IllegalStateException("can't pop an empty stack") } def full: Boolean = buf.size == MAX def empty: Boolean = buf.size == 0 def size = buf.size override def toString = buf.mkString("Stack(", ", ", ")") }
You may want to test the Stack
class in different states: empty, full, with one item, with one item less than capacity,
etc. You may find you have several tests that make sense any time the stack is non-empty. Thus you'd ideally want to run
those same tests for three stack fixture objects: a full stack, a stack with a one item, and a stack with one item less than
capacity. With shared tests, you can factor these tests out into a behavior function, into which you pass the
stack fixture to use when running the tests. So in your AnyFreeSpec
for stack, you'd invoke the
behavior function three times, passing in each of the three stack fixtures so that the shared tests are run for all three fixtures. You
can define a behavior function that encapsulates these shared tests inside the AnyFreeSpec
that uses them. If they are shared
between different AnyFreeSpec
s, however, you could also define them in a separate trait that is mixed into each AnyFreeSpec
that uses them.
For example, here the nonEmptyStack
behavior function (in this case, a behavior method) is
defined in a trait along with another method containing shared tests for non-full stacks:
trait StackBehaviors { this: AnyFreeSpec => def nonEmptyStack(newStack: => Stack[Int], lastItemAdded: Int) { "be non-empty" in { assert(!newStack.empty) } "return the top item on peek" in { assert(newStack.peek === lastItemAdded) } "not remove the top item on peek" in { val stack = newStack val size = stack.size assert(stack.peek === lastItemAdded) assert(stack.size === size) } "remove the top item on pop" in { val stack = newStack val size = stack.size assert(stack.pop === lastItemAdded) assert(stack.size === size - 1) } } def nonFullStack(newStack: => Stack[Int]) { "not be full" in { assert(!newStack.full) } "add to the top on push" in { val stack = newStack val size = stack.size stack.push(7) assert(stack.size === size + 1) assert(stack.peek === 7) } } }
Given these behavior functions, you could invoke them directly, but AnyFreeSpec
offers a DSL for the purpose,
which looks like this:
behave like nonEmptyStack(stackWithOneItem, lastValuePushed) behave like nonFullStack(stackWithOneItem)
If you prefer to use an imperative style to change fixtures, for example by mixing in BeforeAndAfterEach
and
reassigning a stack
var
in beforeEach
, you could write your behavior functions
in the context of that var
, which means you wouldn't need to pass in the stack fixture because it would be
in scope already inside the behavior function. In that case, your code would look like this:
behave like nonEmptyStack // assuming lastValuePushed is also in scope inside nonEmptyStack behave like nonFullStack
The recommended style, however, is the functional, pass-all-the-needed-values-in style. Here's an example:
class SharedTestExampleSpec extends AnyFreeSpec with StackBehaviors { // Stack fixture creation methods def emptyStack = new Stack[Int] def fullStack = { val stack = new Stack[Int] for (i <- 0 until stack.MAX) stack.push(i) stack } def stackWithOneItem = { val stack = new Stack[Int] stack.push(9) stack } def stackWithOneItemLessThanCapacity = { val stack = new Stack[Int] for (i <- 1 to 9) stack.push(i) stack } val lastValuePushed = 9 "A Stack" - { "when empty" - { "should be empty" in { assert(emptyStack.empty) } "should complain on peek" in { assertThrows[IllegalStateException] { emptyStack.peek } } "should complain on pop" in { assertThrows[IllegalStateException] { emptyStack.pop } } } "when it contains one item" - { "should" - { behave like nonEmptyStack(stackWithOneItem, lastValuePushed) behave like nonFullStack(stackWithOneItem) } } "when it contains one item less than capacity" - { "should" - { behave like nonEmptyStack(stackWithOneItemLessThanCapacity, lastValuePushed) behave like nonFullStack(stackWithOneItemLessThanCapacity) } } "when full" - { "should be full" in { assert(fullStack.full) } "should" - { behave like nonEmptyStack(fullStack, lastValuePushed) } "should complain on a push" in { assertThrows[IllegalStateException] { fullStack.push(10) } } } } }
If you load these classes into the Scala interpreter (with scalatest's JAR file on the class path), and execute it, you'll see:
scala> org.scalatest.run(new SharedTestExampleSpec)
SharedTestExampleSpec:
A Stack
when empty
- should be empty
- should complain on peek
- should complain on pop
when it contains one item
should
- be non-empty
- return the top item on peek
- not remove the top item on peek
- remove the top item on pop
- not be full
- add to the top on push
when it contains one item less than capacity
should
- be non-empty
- return the top item on peek
- not remove the top item on peek
- remove the top item on pop
- not be full
- add to the top on push
when full
- should be full
should
- be non-empty
- return the top item on peek
- not remove the top item on peek
- remove the top item on pop
- should complain on a push
One thing to keep in mind when using shared tests is that in ScalaTest, each test in a suite must have a unique name.
If you register the same tests repeatedly in the same suite, one problem you may encounter is an exception at runtime
complaining that multiple tests are being registered with the same test name. A good way to solve this problem in a AnyFreeSpec
is to make sure
each test is in the context of different surrounding description clauses,
because a test's name is the concatenation of its surrounding clauses, followed by the test's text.
For example, the following code in a AnyFreeSpec
would register a test with the name "A Stack when empty should be empty"
:
"A Stack" - { "when empty" - { "should be empty" in { assert(emptyStack.empty) } } } // ...
If the "should be empty"
test was factored out into a behavior function, it could be called repeatedly so long
as each invocation of the behavior function is in the context of a different surrounding description (dash) clauses.
Type members
Inherited classlikes
Class used via an implicit conversion to enable two objects to be compared with
===
and !==
with a Boolean
result and an enforced type constraint between
two object types. For example:
Class used via an implicit conversion to enable two objects to be compared with
===
and !==
with a Boolean
result and an enforced type constraint between
two object types. For example:
assert(a === b) assert(c !== d)
You can also check numeric values against another with a tolerance. Here are some examples:
assert(a === (2.0 +- 0.1)) assert(c !== (2.0 +- 0.1))
- Value parameters:
- leftSide
An object to convert to
Equalizer
, which represents the value on the left side of a===
or!==
invocation.
- Inherited from:
- TripleEqualsSupport
Class used via an implicit conversion to enable any two objects to be compared with
===
and !==
with a Boolean
result and no enforced type constraint between
two object types. For example:
Class used via an implicit conversion to enable any two objects to be compared with
===
and !==
with a Boolean
result and no enforced type constraint between
two object types. For example:
assert(a === b) assert(c !== d)
You can also check numeric values against another with a tolerance. Here are some examples:
assert(a === (2.0 +- 0.1)) assert(c !== (2.0 +- 0.1))
- Value parameters:
- leftSide
An object to convert to
Equalizer
, which represents the value on the left side of a===
or!==
invocation.
- Inherited from:
- TripleEqualsSupport
A class that via an implicit conversion (named convertToFreeSpecStringWrapper
) enables
methods in
, is
, taggedAs
and ignore
,
as well as the dash operator (-
), to be invoked on String
s.
A class that via an implicit conversion (named convertToFreeSpecStringWrapper
) enables
methods in
, is
, taggedAs
and ignore
,
as well as the dash operator (-
), to be invoked on String
s.
- Inherited from:
- AnyFreeSpecLike
A test function taking no arguments and returning an Outcome
.
A test function taking no arguments and returning an Outcome
.
For more detail and examples, see the relevant section in the
documentation for trait fixture.FlatSpec
.
- Inherited from:
- TestSuite
Class that supports the registration of tagged tests.
Class that supports the registration of tagged tests.
Instances of this class are returned by the taggedAs
method of
class FreeSpecStringWrapper
.
- Inherited from:
- AnyFreeSpecLike
Value members
Concrete methods
Returns a user friendly string for this suite, composed of the
simple name of the class (possibly simplified further by removing dollar signs if added by the Scala interpeter) and, if this suite
contains nested suites, the result of invoking toString
on each
of the nested suites, separated by commas and surrounded by parentheses.
Returns a user friendly string for this suite, composed of the
simple name of the class (possibly simplified further by removing dollar signs if added by the Scala interpeter) and, if this suite
contains nested suites, the result of invoking toString
on each
of the nested suites, separated by commas and surrounded by parentheses.
- Returns:
a user-friendly string for this suite
- Definition Classes
- Any
Inherited methods
Returns a TripleEqualsInvocationOnSpread[T]
, given an Spread[T]
, to facilitate
the “<left> should !== (<pivot> +- <tolerance>)
”
syntax of Matchers
.
Returns a TripleEqualsInvocationOnSpread[T]
, given an Spread[T]
, to facilitate
the “<left> should !== (<pivot> +- <tolerance>)
”
syntax of Matchers
.
- Value parameters:
- right
the
Spread[T]
against which to compare the left-hand value
- Returns:
a
TripleEqualsInvocationOnSpread
wrapping the passedSpread[T]
value, withexpectingEqual
set tofalse
.- Inherited from:
- TripleEqualsSupport
Returns a TripleEqualsInvocation[Null]
, given a null
reference, to facilitate
the “<left> should !== null
” syntax
of Matchers
.
Returns a TripleEqualsInvocation[Null]
, given a null
reference, to facilitate
the “<left> should !== null
” syntax
of Matchers
.
- Value parameters:
- right
a null reference
- Returns:
a
TripleEqualsInvocation
wrapping the passednull
value, withexpectingEqual
set tofalse
.- Inherited from:
- TripleEqualsSupport
Returns a TripleEqualsInvocation[T]
, given an object of type T
, to facilitate
the “<left> should !== <right>
” syntax
of Matchers
.
Returns a TripleEqualsInvocation[T]
, given an object of type T
, to facilitate
the “<left> should !== <right>
” syntax
of Matchers
.
- Value parameters:
- right
the right-hand side value for an equality assertion
- Returns:
a
TripleEqualsInvocation
wrapping the passed right value, withexpectingEqual
set tofalse
.- Inherited from:
- TripleEqualsSupport
Returns a TripleEqualsInvocationOnSpread[T]
, given an Spread[T]
, to facilitate
the “<left> should === (<pivot> +- <tolerance>)
”
syntax of Matchers
.
Returns a TripleEqualsInvocationOnSpread[T]
, given an Spread[T]
, to facilitate
the “<left> should === (<pivot> +- <tolerance>)
”
syntax of Matchers
.
- Value parameters:
- right
the
Spread[T]
against which to compare the left-hand value
- Returns:
a
TripleEqualsInvocationOnSpread
wrapping the passedSpread[T]
value, withexpectingEqual
set totrue
.- Inherited from:
- TripleEqualsSupport
Returns a TripleEqualsInvocation[Null]
, given a null
reference, to facilitate
the “<left> should === null
” syntax
of Matchers
.
Returns a TripleEqualsInvocation[Null]
, given a null
reference, to facilitate
the “<left> should === null
” syntax
of Matchers
.
- Value parameters:
- right
a null reference
- Returns:
a
TripleEqualsInvocation
wrapping the passednull
value, withexpectingEqual
set totrue
.- Inherited from:
- TripleEqualsSupport
Returns a TripleEqualsInvocation[T]
, given an object of type T
, to facilitate
the “<left> should === <right>
” syntax
of Matchers
.
Returns a TripleEqualsInvocation[T]
, given an object of type T
, to facilitate
the “<left> should === <right>
” syntax
of Matchers
.
- Value parameters:
- right
the right-hand side value for an equality assertion
- Returns:
a
TripleEqualsInvocation
wrapping the passed right value, withexpectingEqual
set totrue
.- Inherited from:
- TripleEqualsSupport
Returns an Alerter
that during test execution will forward strings passed to its
apply
method to the current reporter. If invoked in a constructor, it
will register the passed string for forwarding later during test execution. If invoked while this
AnyFreeSpec
is being executed, such as from inside a test function, it will forward the information to
the current reporter immediately. If invoked at any other time, it will
print to the standard output. This method can be called safely by any thread.
Returns an Alerter
that during test execution will forward strings passed to its
apply
method to the current reporter. If invoked in a constructor, it
will register the passed string for forwarding later during test execution. If invoked while this
AnyFreeSpec
is being executed, such as from inside a test function, it will forward the information to
the current reporter immediately. If invoked at any other time, it will
print to the standard output. This method can be called safely by any thread.
- Inherited from:
- AnyFreeSpecLike
Assert that a boolean condition, described in String
message
, is true.
If the condition is true
, this method returns normally.
Else, it throws TestFailedException
with a helpful error message
appended with the String
obtained by invoking toString
on the
specified clue
as the exception's detail message.
Assert that a boolean condition, described in String
message
, is true.
If the condition is true
, this method returns normally.
Else, it throws TestFailedException
with a helpful error message
appended with the String
obtained by invoking toString
on the
specified clue
as the exception's detail message.
This method is implemented in terms of a Scala macro that will generate a more helpful error message for expressions of this form:
-
assert(a == b, "a good clue")
-
assert(a != b, "a good clue")
-
assert(a === b, "a good clue")
-
assert(a !== b, "a good clue")
-
assert(a > b, "a good clue")
-
assert(a >= b, "a good clue")
-
assert(a < b, "a good clue")
-
assert(a <= b, "a good clue")
-
assert(a startsWith "prefix", "a good clue")
-
assert(a endsWith "postfix", "a good clue")
-
assert(a contains "something", "a good clue")
-
assert(a eq b, "a good clue")
-
assert(a ne b, "a good clue")
-
assert(a > 0 && b > 5, "a good clue")
-
assert(a > 0 || b > 5, "a good clue")
-
assert(a.isEmpty, "a good clue")
-
assert(!a.isEmpty, "a good clue")
-
assert(a.isInstanceOf[String], "a good clue")
-
assert(a.length == 8, "a good clue")
-
assert(a.size == 8, "a good clue")
-
assert(a.exists(_ == 8), "a good clue")
At this time, any other form of expression will just get a TestFailedException
with message saying the given
expression was false. In the future, we will enhance this macro to give helpful error messages in more situations.
In ScalaTest 2.0, however, this behavior was sufficient to allow the ===
that returns Boolean
to be the default in tests. This makes ===
consistent between tests and production
code.
- Value parameters:
- clue
An objects whose
toString
method returns a message to include in a failure report.- condition
the boolean condition to assert
- Throws:
- NullArgumentException
if
message
isnull
.- TestFailedException
if the condition is
false
.
- Inherited from:
- Assertions
Assert that a boolean condition is true.
If the condition is true
, this method returns normally.
Else, it throws TestFailedException
.
Assert that a boolean condition is true.
If the condition is true
, this method returns normally.
Else, it throws TestFailedException
.
This method is implemented in terms of a Scala macro that will generate a more helpful error message for expressions of this form:
-
assert(a == b)
-
assert(a != b)
-
assert(a === b)
-
assert(a !== b)
-
assert(a > b)
-
assert(a >= b)
-
assert(a < b)
-
assert(a <= b)
-
assert(a startsWith "prefix")
-
assert(a endsWith "postfix")
-
assert(a contains "something")
-
assert(a eq b)
-
assert(a ne b)
-
assert(a > 0 && b > 5)
-
assert(a > 0 || b > 5)
-
assert(a.isEmpty)
-
assert(!a.isEmpty)
-
assert(a.isInstanceOf[String])
-
assert(a.length == 8)
-
assert(a.size == 8)
-
assert(a.exists(_ == 8))
At this time, any other form of expression will get a TestFailedException
with message saying the given
expression was false. In the future, we will enhance this macro to give helpful error messages in more situations.
In ScalaTest 2.0, however, this behavior was sufficient to allow the ===
that returns Boolean
to be the default in tests. This makes ===
consistent between tests and production
code.
- Value parameters:
- condition
the boolean condition to assert
- Throws:
- TestFailedException
if the condition is
false
.
- Inherited from:
- Assertions
Asserts that a given string snippet of code passes both the Scala parser and type checker.
Asserts that a given string snippet of code passes both the Scala parser and type checker.
You can use this to make sure a snippet of code compiles:
assertCompiles("val a: Int = 1")
Although assertCompiles
is implemented with a macro that determines at compile time whether
the snippet of code represented by the passed string compiles, errors (i.e.,
snippets of code that do not compile) are reported as test failures at runtime.
- Value parameters:
- code
the snippet of code that should compile
- Inherited from:
- Assertions
Asserts that a given string snippet of code does not pass either the Scala parser or type checker.
Asserts that a given string snippet of code does not pass either the Scala parser or type checker.
Often when creating libraries you may wish to ensure that certain arrangements of code that
represent potential “user errors” do not compile, so that your library is more error resistant.
ScalaTest's Assertions
trait includes the following syntax for that purpose:
assertDoesNotCompile("val a: String = \"a string")
Although assertDoesNotCompile
is implemented with a macro that determines at compile time whether
the snippet of code represented by the passed string doesn't compile, errors (i.e.,
snippets of code that do compile) are reported as test failures at runtime.
Note that the difference between assertTypeError
and assertDoesNotCompile
is
that assertDoesNotCompile
will succeed if the given code does not compile for any reason,
whereas assertTypeError
will only succeed if the given code does not compile because of
a type error. If the given code does not compile because of a syntax error, for example, assertDoesNotCompile
will return normally but assertTypeError
will throw a TestFailedException
.
- Value parameters:
- code
the snippet of code that should not type check
- Inherited from:
- Assertions
Assert that the value passed as expected
equals the value passed as actual
.
If the actual
value equals the expected
value
(as determined by ==
), assertResult
returns
normally. Else, assertResult
throws a
TestFailedException
whose detail message includes the expected and actual values.
Assert that the value passed as expected
equals the value passed as actual
.
If the actual
value equals the expected
value
(as determined by ==
), assertResult
returns
normally. Else, assertResult
throws a
TestFailedException
whose detail message includes the expected and actual values.
- Value parameters:
- actual
the actual value, which should equal the passed
expected
value- expected
the expected value
- Throws:
- TestFailedException
if the passed
actual
value does not equal the passedexpected
value.
- Inherited from:
- Assertions
Assert that the value passed as expected
equals the value passed as actual
.
If the actual
equals the expected
(as determined by ==
), assertResult
returns
normally. Else, if actual
is not equal to expected
, assertResult
throws a
TestFailedException
whose detail message includes the expected and actual values, as well as the String
obtained by invoking toString
on the passed clue
.
Assert that the value passed as expected
equals the value passed as actual
.
If the actual
equals the expected
(as determined by ==
), assertResult
returns
normally. Else, if actual
is not equal to expected
, assertResult
throws a
TestFailedException
whose detail message includes the expected and actual values, as well as the String
obtained by invoking toString
on the passed clue
.
- Value parameters:
- actual
the actual value, which should equal the passed
expected
value- clue
An object whose
toString
method returns a message to include in a failure report.- expected
the expected value
- Throws:
- TestFailedException
if the passed
actual
value does not equal the passedexpected
value.
- Inherited from:
- Assertions
Ensure that an expected exception is thrown by the passed function value. The thrown exception must be an instance of the
type specified by the type parameter of this method. This method invokes the passed
function. If the function throws an exception that's an instance of the specified type,
this method returns Succeeded
. Else, whether the passed function returns normally
or completes abruptly with a different exception, this method throws TestFailedException
.
Ensure that an expected exception is thrown by the passed function value. The thrown exception must be an instance of the
type specified by the type parameter of this method. This method invokes the passed
function. If the function throws an exception that's an instance of the specified type,
this method returns Succeeded
. Else, whether the passed function returns normally
or completes abruptly with a different exception, this method throws TestFailedException
.
Note that the type specified as this method's type parameter may represent any subtype of
AnyRef
, not just Throwable
or one of its subclasses. In
Scala, exceptions can be caught based on traits they implement, so it may at times make sense
to specify a trait that the intercepted exception's class must mix in. If a class instance is
passed for a type that could not possibly be used to catch an exception (such as String
,
for example), this method will complete abruptly with a TestFailedException
.
Also note that the difference between this method and intercept
is that this method
does not return the expected exception, so it does not let you perform further assertions on
that exception. Instead, this method returns Succeeded
, which means it can
serve as the last statement in an async- or safe-style suite. It also indicates to the reader
of the code that nothing further is expected about the thrown exception other than its type.
The recommended usage is to use assertThrows
by default, intercept
only when you
need to inspect the caught exception further.
- Value parameters:
- classTag
an implicit
ClassTag
representing the type of the specified type parameter.- f
the function value that should throw the expected exception
- Returns:
the
Succeeded
singleton, if an exception of the expected type is thrown- Throws:
- TestFailedException
if the passed function does not complete abruptly with an exception that's an instance of the specified type.
- Inherited from:
- Assertions
Asserts that a given string snippet of code does not pass the Scala type checker, failing if the given snippet does not pass the Scala parser.
Asserts that a given string snippet of code does not pass the Scala type checker, failing if the given snippet does not pass the Scala parser.
Often when creating libraries you may wish to ensure that certain arrangements of code that
represent potential “user errors” do not compile, so that your library is more error resistant.
ScalaTest's Assertions
trait includes the following syntax for that purpose:
assertTypeError("val a: String = 1")
Although assertTypeError
is implemented with a macro that determines at compile time whether
the snippet of code represented by the passed string type checks, errors (i.e.,
snippets of code that do type check) are reported as test failures at runtime.
Note that the difference between assertTypeError
and assertDoesNotCompile
is
that assertDoesNotCompile
will succeed if the given code does not compile for any reason,
whereas assertTypeError
will only succeed if the given code does not compile because of
a type error. If the given code does not compile because of a syntax error, for example, assertDoesNotCompile
will return normally but assertTypeError
will throw a TestFailedException
.
- Value parameters:
- code
the snippet of code that should not type check
- Inherited from:
- Assertions
Assume that a boolean condition, described in String
message
, is true.
If the condition is true
, this method returns normally.
Else, it throws TestCanceledException
with a helpful error message
appended with String
obtained by invoking toString
on the
specified clue
as the exception's detail message.
Assume that a boolean condition, described in String
message
, is true.
If the condition is true
, this method returns normally.
Else, it throws TestCanceledException
with a helpful error message
appended with String
obtained by invoking toString
on the
specified clue
as the exception's detail message.
This method is implemented in terms of a Scala macro that will generate a more helpful error message for expressions of this form:
-
assume(a == b, "a good clue")
-
assume(a != b, "a good clue")
-
assume(a === b, "a good clue")
-
assume(a !== b, "a good clue")
-
assume(a > b, "a good clue")
-
assume(a >= b, "a good clue")
-
assume(a < b, "a good clue")
-
assume(a <= b, "a good clue")
-
assume(a startsWith "prefix", "a good clue")
-
assume(a endsWith "postfix", "a good clue")
-
assume(a contains "something", "a good clue")
-
assume(a eq b, "a good clue")
-
assume(a ne b, "a good clue")
-
assume(a > 0 && b > 5, "a good clue")
-
assume(a > 0 || b > 5, "a good clue")
-
assume(a.isEmpty, "a good clue")
-
assume(!a.isEmpty, "a good clue")
-
assume(a.isInstanceOf[String], "a good clue")
-
assume(a.length == 8, "a good clue")
-
assume(a.size == 8, "a good clue")
-
assume(a.exists(_ == 8), "a good clue")
At this time, any other form of expression will just get a TestCanceledException
with message saying the given
expression was false. In the future, we will enhance this macro to give helpful error messages in more situations.
In ScalaTest 2.0, however, this behavior was sufficient to allow the ===
that returns Boolean
to be the default in tests. This makes ===
consistent between tests and production
code.
- Value parameters:
- clue
An objects whose
toString
method returns a message to include in a failure report.- condition
the boolean condition to assume
- Throws:
- NullArgumentException
if
message
isnull
.- TestCanceledException
if the condition is
false
.
- Inherited from:
- Assertions
Assume that a boolean condition is true.
If the condition is true
, this method returns normally.
Else, it throws TestCanceledException
.
Assume that a boolean condition is true.
If the condition is true
, this method returns normally.
Else, it throws TestCanceledException
.
This method is implemented in terms of a Scala macro that will generate a more helpful error message for expressions of this form:
-
assume(a == b)
-
assume(a != b)
-
assume(a === b)
-
assume(a !== b)
-
assume(a > b)
-
assume(a >= b)
-
assume(a < b)
-
assume(a <= b)
-
assume(a startsWith "prefix")
-
assume(a endsWith "postfix")
-
assume(a contains "something")
-
assume(a eq b)
-
assume(a ne b)
-
assume(a > 0 && b > 5)
-
assume(a > 0 || b > 5)
-
assume(a.isEmpty)
-
assume(!a.isEmpty)
-
assume(a.isInstanceOf[String])
-
assume(a.length == 8)
-
assume(a.size == 8)
-
assume(a.exists(_ == 8))
At this time, any other form of expression will just get a TestCanceledException
with message saying the given
expression was false. In the future, we will enhance this macro to give helpful error messages in more situations.
In ScalaTest 2.0, however, this behavior was sufficient to allow the ===
that returns Boolean
to be the default in tests. This makes ===
consistent between tests and production
code.
- Value parameters:
- condition
the boolean condition to assume
- Throws:
- TestCanceledException
if the condition is
false
.
- Inherited from:
- Assertions
Throws TestCanceledException
, with the passed
Throwable
cause, to indicate a test failed.
The getMessage
method of the thrown TestCanceledException
will return cause.toString
.
Throws TestCanceledException
, with the passed
Throwable
cause, to indicate a test failed.
The getMessage
method of the thrown TestCanceledException
will return cause.toString
.
- Value parameters:
- cause
a
Throwable
that indicates the cause of the cancellation.
- Throws:
- NullArgumentException
if
cause
isnull
- Inherited from:
- Assertions
Throws TestCanceledException
, with the passed
String
message
as the exception's detail
message and Throwable
cause, to indicate a test failed.
Throws TestCanceledException
, with the passed
String
message
as the exception's detail
message and Throwable
cause, to indicate a test failed.
- Value parameters:
- cause
A
Throwable
that indicates the cause of the failure.- message
A message describing the failure.
- Throws:
- NullArgumentException
if
message
orcause
isnull
- Inherited from:
- Assertions
Throws TestCanceledException
, with the passed
String
message
as the exception's detail
message, to indicate a test was canceled.
Throws TestCanceledException
, with the passed
String
message
as the exception's detail
message, to indicate a test was canceled.
- Value parameters:
- message
A message describing the cancellation.
- Throws:
- NullArgumentException
if
message
isnull
- Inherited from:
- Assertions
Throws TestCanceledException
to indicate a test was canceled.
Throws TestCanceledException
to indicate a test was canceled.
- Inherited from:
- Assertions
- Definition Classes
- TripleEquals -> TripleEqualsSupport
- Inherited from:
- TripleEquals
- Definition Classes
- TripleEquals -> TripleEqualsSupport
- Inherited from:
- TripleEquals
Returns an Equality[A]
for any type A
that determines equality
by first calling .deep
on any Array
(on either the left or right side),
then comparing the resulting objects with ==
.
Returns an Equality[A]
for any type A
that determines equality
by first calling .deep
on any Array
(on either the left or right side),
then comparing the resulting objects with ==
.
- Returns:
a default
Equality
for typeA
- Inherited from:
- TripleEqualsSupport
Executes one or more tests in this Suite
, printing results to the standard output.
Executes one or more tests in this Suite
, printing results to the standard output.
This method invokes run
on itself, passing in values that can be configured via the parameters to this
method, all of which have default values. This behavior is convenient when working with ScalaTest in the Scala interpreter.
Here's a summary of this method's parameters and how you can use them:
The testName
parameter
If you leave testName
at its default value (of null
), this method will pass None
to
the testName
parameter of run
, and as a result all the tests in this suite will be executed. If you
specify a testName
, this method will pass Some(testName)
to run
, and only that test
will be run. Thus to run all tests in a suite from the Scala interpreter, you can write:
scala> (new ExampleSuite).execute()
(The above syntax actually invokes the overloaded parameterless form of execute
, which calls this form with its default parameter values.)
To run just the test named "my favorite test"
in a suite from the Scala interpreter, you would write:
scala> (new ExampleSuite).execute("my favorite test")
Or:
scala> (new ExampleSuite).execute(testName = "my favorite test")
The configMap
parameter
If you provide a value for the configMap
parameter, this method will pass it to run
. If not, the default value
of an empty Map
will be passed. For more information on how to use a config map to configure your test suites, see
the config map section in the main documentation for this trait. Here's an example in which you configure
a run with the name of an input file:
scala> (new ExampleSuite).execute(configMap = Map("inputFileName" -> "in.txt")
The color
parameter
If you leave the color
parameter unspecified, this method will configure the reporter it passes to run
to print
to the standard output in color (via ansi escape characters). If you don't want color output, specify false for color
, like this:
scala> (new ExampleSuite).execute(color = false)
The durations
parameter
If you leave the durations
parameter unspecified, this method will configure the reporter it passes to run
to
not print durations for tests and suites to the standard output. If you want durations printed, specify true for durations
,
like this:
scala> (new ExampleSuite).execute(durations = true)
The shortstacks
and fullstacks
parameters
If you leave both the shortstacks
and fullstacks
parameters unspecified, this method will configure the reporter
it passes to run
to not print stack traces for failed tests if it has a stack depth that identifies the offending
line of test code. If you prefer a short stack trace (10 to 15 stack frames) to be printed with any test failure, specify true for
shortstacks
:
scala> (new ExampleSuite).execute(shortstacks = true)
For full stack traces, set fullstacks
to true:
scala> (new ExampleSuite).execute(fullstacks = true)
If you specify true for both shortstacks
and fullstacks
, you'll get full stack traces.
The stats
parameter
If you leave the stats
parameter unspecified, this method will not fire RunStarting
and either RunCompleted
or RunAborted
events to the reporter it passes to run
.
If you specify true for stats
, this method will fire the run events to the reporter, and the reporter will print the
expected test count before the run, and various statistics after, including the number of suites completed and number of tests that
succeeded, failed, were ignored or marked pending. Here's how you get the stats:
scala> (new ExampleSuite).execute(stats = true)
To summarize, this method will pass to run
:
-
testName
-None
if this method'stestName
parameter is left at its default value ofnull
, elseSome(testName)
. -
reporter
- a reporter that prints to the standard output -
stopper
- aStopper
whoseapply
method always returnsfalse
-
filter
- aFilter
constructed withNone
fortagsToInclude
andSet()
fortagsToExclude
-
configMap
- theconfigMap
passed to this method -
distributor
-None
-
tracker
- a newTracker
Note: In ScalaTest, the terms "execute" and "run" basically mean the same thing and
can be used interchangably. The reason this method isn't named run
is that it takes advantage of
default arguments, and you can't mix overloaded methods and default arguments in Scala. (If named run
,
this method would have the same name but different arguments than the main run
method that
takes seven arguments. Thus it would overload and couldn't be used with default argument values.)
Design note: This method has two "features" that may seem unidiomatic. First, the default value of testName
is null
.
Normally in Scala the type of testName
would be Option[String]
and the default value would
be None
, as it is in this trait's run
method. The null
value is used here for two reasons. First, in
ScalaTest 1.5, execute
was changed from four overloaded methods to one method with default values, taking advantage of
the default and named parameters feature introduced in Scala 2.8.
To not break existing source code, testName
needed to have type String
, as it did in two of the overloaded
execute
methods prior to 1.5. The other reason is that execute
has always been designed to be called primarily
from an interpeter environment, such as the Scala REPL (Read-Evaluate-Print-Loop). In an interpreter environment, minimizing keystrokes is king.
A String
type with a null
default value lets users type suite.execute("my test name")
rather than
suite.execute(Some("my test name"))
, saving several keystrokes.
The second non-idiomatic feature is that shortstacks
and fullstacks
are all lower case rather than
camel case. This is done to be consistent with the Shell
, which also uses those forms. The reason
lower case is used in the Shell
is to save keystrokes in an interpreter environment. Most Unix commands, for
example, are all lower case, making them easier and quicker to type. In the ScalaTest
Shell
, methods like shortstacks
, fullstacks
, and nostats
, etc., are
designed to be all lower case so they feel more like shell commands than methods.
- Value parameters:
- color
a boolean that configures whether output is printed in color
- configMap
a
Map
of key-value pairs that can be used by the executingSuite
of tests.- durations
a boolean that configures whether test and suite durations are printed to the standard output
- fullstacks
a boolean that configures whether full stack traces should be printed for test failures
- shortstacks
a boolean that configures whether short stack traces should be printed for test failures
- stats
a boolean that configures whether test and suite statistics are printed to the standard output
- testName
the name of one test to run.
- Throws:
- IllegalArgumentException
if
testName
is defined, but no test with the specified test name exists in thisSuite
- NullArgumentException
if the passed
configMap
parameter isnull
.
- Inherited from:
- Suite
The total number of tests that are expected to run when this Suite
's run
method is invoked.
The total number of tests that are expected to run when this Suite
's run
method is invoked.
This trait's implementation of this method returns the sum of:
-
the size of the
testNames
List
, minus the number of tests marked as ignored and any tests that are exluded by the passedFilter
-
the sum of the values obtained by invoking
expectedTestCount
on every nestedSuite
contained innestedSuites
- Value parameters:
- filter
a
Filter
with which to filter tests to count based on their tags
- Inherited from:
- Suite
Throws TestFailedException
, with the passed
Throwable
cause, to indicate a test failed.
The getMessage
method of the thrown TestFailedException
will return cause.toString
.
Throws TestFailedException
, with the passed
Throwable
cause, to indicate a test failed.
The getMessage
method of the thrown TestFailedException
will return cause.toString
.
- Value parameters:
- cause
a
Throwable
that indicates the cause of the failure.
- Throws:
- NullArgumentException
if
cause
isnull
- Inherited from:
- Assertions
Throws TestFailedException
, with the passed
String
message
as the exception's detail
message and Throwable
cause, to indicate a test failed.
Throws TestFailedException
, with the passed
String
message
as the exception's detail
message and Throwable
cause, to indicate a test failed.
- Value parameters:
- cause
A
Throwable
that indicates the cause of the failure.- message
A message describing the failure.
- Throws:
- NullArgumentException
if
message
orcause
isnull
- Inherited from:
- Assertions
Throws TestFailedException
, with the passed
String
message
as the exception's detail
message, to indicate a test failed.
Throws TestFailedException
, with the passed
String
message
as the exception's detail
message, to indicate a test failed.
- Value parameters:
- message
A message describing the failure.
- Throws:
- NullArgumentException
if
message
isnull
- Inherited from:
- Assertions
Throws TestFailedException
to indicate a test failed.
Throws TestFailedException
to indicate a test failed.
- Inherited from:
- Assertions
Returns an Informer
that during test execution will forward strings passed to its
apply
method to the current reporter. If invoked in a constructor, it
will register the passed string for forwarding later during test execution. If invoked from inside a scope,
it will forward the information to the current reporter immediately. If invoked from inside a test function,
it will record the information and forward it to the current reporter only after the test completed, as recordedEvents
of the test completed event, such as TestSucceeded
. If invoked at any other time, it will print to the standard output.
This method can be called safely by any thread.
Returns an Informer
that during test execution will forward strings passed to its
apply
method to the current reporter. If invoked in a constructor, it
will register the passed string for forwarding later during test execution. If invoked from inside a scope,
it will forward the information to the current reporter immediately. If invoked from inside a test function,
it will record the information and forward it to the current reporter only after the test completed, as recordedEvents
of the test completed event, such as TestSucceeded
. If invoked at any other time, it will print to the standard output.
This method can be called safely by any thread.
- Inherited from:
- AnyFreeSpecLike
Intercept and return an exception that's expected to
be thrown by the passed function value. The thrown exception must be an instance of the
type specified by the type parameter of this method. This method invokes the passed
function. If the function throws an exception that's an instance of the specified type,
this method returns that exception. Else, whether the passed function returns normally
or completes abruptly with a different exception, this method throws TestFailedException
.
Intercept and return an exception that's expected to
be thrown by the passed function value. The thrown exception must be an instance of the
type specified by the type parameter of this method. This method invokes the passed
function. If the function throws an exception that's an instance of the specified type,
this method returns that exception. Else, whether the passed function returns normally
or completes abruptly with a different exception, this method throws TestFailedException
.
Note that the type specified as this method's type parameter may represent any subtype of
AnyRef
, not just Throwable
or one of its subclasses. In
Scala, exceptions can be caught based on traits they implement, so it may at times make sense
to specify a trait that the intercepted exception's class must mix in. If a class instance is
passed for a type that could not possibly be used to catch an exception (such as String
,
for example), this method will complete abruptly with a TestFailedException
.
Also note that the difference between this method and assertThrows
is that this method
returns the expected exception, so it lets you perform further assertions on
that exception. By contrast, the assertThrows
method returns Succeeded
, which means it can
serve as the last statement in an async- or safe-style suite. assertThrows
also indicates to the reader
of the code that nothing further is expected about the thrown exception other than its type.
The recommended usage is to use assertThrows
by default, intercept
only when you
need to inspect the caught exception further.
- Value parameters:
- classTag
an implicit
ClassTag
representing the type of the specified type parameter.- f
the function value that should throw the expected exception
- Returns:
the intercepted exception, if it is of the expected type
- Throws:
- TestFailedException
if the passed function does not complete abruptly with an exception that's an instance of the specified type.
- Inherited from:
- Assertions
- Definition Classes
- TripleEquals -> TripleEqualsSupport
- Inherited from:
- TripleEquals
Returns a Documenter
that during test execution will forward strings passed to its
apply
method to the current reporter. If invoked in a constructor, it
will register the passed string for forwarding later during test execution. If invoked from inside a scope,
it will forward the information to the current reporter immediately. If invoked from inside a test function,
it will record the information and forward it to the current reporter only after the test completed, as recordedEvents
of the test completed event, such as TestSucceeded
. If invoked at any other time, it will print to the standard output.
This method can be called safely by any thread.
Returns a Documenter
that during test execution will forward strings passed to its
apply
method to the current reporter. If invoked in a constructor, it
will register the passed string for forwarding later during test execution. If invoked from inside a scope,
it will forward the information to the current reporter immediately. If invoked from inside a test function,
it will record the information and forward it to the current reporter only after the test completed, as recordedEvents
of the test completed event, such as TestSucceeded
. If invoked at any other time, it will print to the standard output.
This method can be called safely by any thread.
- Inherited from:
- AnyFreeSpecLike
An immutable IndexedSeq
of this Suite
object's nested Suite
s. If this Suite
contains no nested Suite
s,
this method returns an empty IndexedSeq
. This trait's implementation of this method returns an empty List
.
An immutable IndexedSeq
of this Suite
object's nested Suite
s. If this Suite
contains no nested Suite
s,
this method returns an empty IndexedSeq
. This trait's implementation of this method returns an empty List
.
- Inherited from:
- Suite
Returns a Notifier
that during test execution will forward strings passed to its
apply
method to the current reporter. If invoked in a constructor, it
will register the passed string for forwarding later during test execution. If invoked while this
AnyFreeSpec
is being executed, such as from inside a test function, it will forward the information to
the current reporter immediately. If invoked at any other time, it will
print to the standard output. This method can be called safely by any thread.
Returns a Notifier
that during test execution will forward strings passed to its
apply
method to the current reporter. If invoked in a constructor, it
will register the passed string for forwarding later during test execution. If invoked while this
AnyFreeSpec
is being executed, such as from inside a test function, it will forward the information to
the current reporter immediately. If invoked at any other time, it will
print to the standard output. This method can be called safely by any thread.
- Inherited from:
- AnyFreeSpecLike
Throws TestPendingException
to indicate a test is pending.
Throws TestPendingException
to indicate a test is pending.
A pending test is one that has been given a name but is not yet implemented. The purpose of pending tests is to facilitate a style of testing in which documentation of behavior is sketched out before tests are written to verify that behavior (and often, the before the behavior of the system being tested is itself implemented). Such sketches form a kind of specification of what tests and functionality to implement later.
To support this style of testing, a test can be given a name that specifies one
bit of behavior required by the system being tested. The test can also include some code that
sends more information about the behavior to the reporter when the tests run. At the end of the test,
it can call method pending
, which will cause it to complete abruptly with TestPendingException
.
Because tests in ScalaTest can be designated as pending with TestPendingException
, both the test name and any information
sent to the reporter when running the test can appear in the report of a test run. (In other words,
the code of a pending test is executed just like any other test.) However, because the test completes abruptly
with TestPendingException
, the test will be reported as pending, to indicate
the actual test, and possibly the functionality it is intended to test, has not yet been implemented.
Note: This method always completes abruptly with a TestPendingException
. Thus it always has a side
effect. Methods with side effects are usually invoked with parentheses, as in pending()
. This
method is defined as a parameterless method, in flagrant contradiction to recommended Scala style, because it
forms a kind of DSL for pending tests. It enables tests in suites such as FunSuite
or FunSpec
to be denoted by placing "(pending)
" after the test name, as in:
test("that style rules are not laws") (pending)
Readers of the code see "pending" in parentheses, which looks like a little note attached to the test name to indicate
it is pending. Whereas "(pending())
looks more like a method call, "(pending)
" lets readers
stay at a higher level, forgetting how it is implemented and just focusing on the intent of the programmer who wrote the code.
- Inherited from:
- Assertions
Execute the passed block of code, and if it completes abruptly, throw TestPendingException
, else
throw TestFailedException
.
Execute the passed block of code, and if it completes abruptly, throw TestPendingException
, else
throw TestFailedException
.
This method can be used to temporarily change a failing test into a pending test in such a way that it will
automatically turn back into a failing test once the problem originally causing the test to fail has been fixed.
At that point, you need only remove the pendingUntilFixed
call. In other words, a
pendingUntilFixed
surrounding a block of code that isn't broken is treated as a test failure.
The motivation for this behavior is to encourage people to remove pendingUntilFixed
calls when
there are no longer needed.
This method facilitates a style of testing in which tests are written before the code they test. Sometimes you may
encounter a test failure that requires more functionality than you want to tackle without writing more tests. In this
case you can mark the bit of test code causing the failure with pendingUntilFixed
. You can then write more
tests and functionality that eventually will get your production code to a point where the original test won't fail anymore.
At this point the code block marked with pendingUntilFixed
will no longer throw an exception (because the
problem has been fixed). This will in turn cause pendingUntilFixed
to throw TestFailedException
with a detail message explaining you need to go back and remove the pendingUntilFixed
call as the problem orginally
causing your test code to fail has been fixed.
- Value parameters:
- f
a block of code, which if it completes abruptly, should trigger a
TestPendingException
- Throws:
- TestPendingException
if the passed block of code completes abruptly with an
Exception
orAssertionError
- Inherited from:
- Assertions
- Inherited from:
- AnyFreeSpecLike
- Inherited from:
- AnyFreeSpecLike
The fully qualified class name of the rerunner to rerun this suite. This implementation will look at this.getClass and see if it is either an accessible Suite, or it has a WrapWith annotation. If so, it returns the fully qualified class name wrapped in a Some, or else it returns None.
The fully qualified class name of the rerunner to rerun this suite. This implementation will look at this.getClass and see if it is either an accessible Suite, or it has a WrapWith annotation. If so, it returns the fully qualified class name wrapped in a Some, or else it returns None.
- Inherited from:
- Suite
Run a test. This trait's implementation runs the test registered with the name specified by
testName
. Each test's name is a concatenation of the text of all describers surrounding a test,
from outside in, and the test's spec text, with one space placed between each item. (See the documentation
for testNames
for an example.)
Run a test. This trait's implementation runs the test registered with the name specified by
testName
. Each test's name is a concatenation of the text of all describers surrounding a test,
from outside in, and the test's spec text, with one space placed between each item. (See the documentation
for testNames
for an example.)
- Value parameters:
- args
the
Args
for this run- testName
the name of one test to execute.
- Returns:
a
Status
object that indicates when the test started by this method has completed, and whether or not it failed .- Throws:
- NullArgumentException
if any of
testName
,reporter
,stopper
, orconfigMap
isnull
.
- Definition Classes
- Inherited from:
- AnyFreeSpecLike
Run zero to many of this AnyFreeSpec
's tests.
Run zero to many of this AnyFreeSpec
's tests.
This method takes a testName
parameter that optionally specifies a test to invoke.
If testName
is Some
, this trait's implementation of this method
invokes runTest
on this object, passing in:
-
testName
- theString
value of thetestName
Option
passed to this method -
reporter
- theReporter
passed to this method, or one that wraps and delegates to it -
stopper
- theStopper
passed to this method, or one that wraps and delegates to it -
configMap
- theconfigMap
passed to this method, or one that wraps and delegates to it
This method takes a Set
of tag names that should be included (tagsToInclude
), and a Set
that should be excluded (tagsToExclude
), when deciding which of this Suite
's tests to execute.
If tagsToInclude
is empty, all tests will be executed
except those those belonging to tags listed in the tagsToExclude
Set
. If tagsToInclude
is non-empty, only tests
belonging to tags mentioned in tagsToInclude
, and not mentioned in tagsToExclude
will be executed. However, if testName
is Some
, tagsToInclude
and tagsToExclude
are essentially ignored.
Only if testName
is None
will tagsToInclude
and tagsToExclude
be consulted to
determine which of the tests named in the testNames
Set
should be run. For more information on trait tags, see the main documentation for this trait.
If testName
is None
, this trait's implementation of this method
invokes testNames
on this Suite
to get a Set
of names of tests to potentially execute.
(A testNames
value of None
essentially acts as a wildcard that means all tests in
this Suite
that are selected by tagsToInclude
and tagsToExclude
should be executed.)
For each test in the testName
Set
, in the order
they appear in the iterator obtained by invoking the elements
method on the Set
, this trait's implementation
of this method checks whether the test should be run based on the tagsToInclude
and tagsToExclude
Set
s.
If so, this implementation invokes runTest
, passing in:
-
testName
- theString
name of the test to run (which will be one of the names in thetestNames
Set
) -
reporter
- theReporter
passed to this method, or one that wraps and delegates to it -
stopper
- theStopper
passed to this method, or one that wraps and delegates to it -
configMap
- theconfigMap
passed to this method, or one that wraps and delegates to it
- Value parameters:
- args
the
Args
for this run- testName
an optional name of one test to run. If
None
, all relevant tests should be run. I.e.,None
acts like a wildcard that means run all relevant tests in thisSuite
.
- Returns:
a
Status
object that indicates when all tests started by this method have completed, and whether or not a failure occurred.- Throws:
- IllegalArgumentException
if
testName
is defined, but no test with the specified test name exists in thisSuite
- NullArgumentException
if any of the passed parameters is
null
.
- Definition Classes
- AnyFreeSpecLike -> Suite
- Inherited from:
- AnyFreeSpecLike
A string ID for this Suite
that is intended to be unique among all suites reported during a run.
A string ID for this Suite
that is intended to be unique among all suites reported during a run.
This trait's
implementation of this method returns the fully qualified name of this object's class.
Each suite reported during a run will commonly be an instance of a different Suite
class,
and in such cases, this default implementation of this method will suffice. However, in special cases
you may need to override this method to ensure it is unique for each reported suite. For example, if you write
a Suite
subclass that reads in a file whose name is passed to its constructor and dynamically
creates a suite of tests based on the information in that file, you will likely need to override this method
in your Suite
subclass, perhaps by appending the pathname of the file to the fully qualified class name.
That way if you run a suite of tests based on a directory full of these files, you'll have unique suite IDs for
each reported suite.
The suite ID is intended to be unique, because ScalaTest does not enforce that it is unique. If it is not unique, then you may not be able to uniquely identify a particular test of a particular suite. This ability is used, for example, to dynamically tag tests as having failed in the previous run when rerunning only failed tests.
- Returns:
this
Suite
object's ID.- Inherited from:
- Suite
A user-friendly suite name for this Suite
.
A user-friendly suite name for this Suite
.
This trait's
implementation of this method returns the simple name of this object's class. This
trait's implementation of runNestedSuites
calls this method to obtain a
name for Report
s to pass to the suiteStarting
, suiteCompleted
,
and suiteAborted
methods of the Reporter
.
- Returns:
this
Suite
object's suite name.- Inherited from:
- Suite
A Map
whose keys are String
names of tagged tests and whose associated values are
the Set
of tags for the test. If this AnyFreeSpec
contains no tags, this method returns an empty Map
.
A Map
whose keys are String
names of tagged tests and whose associated values are
the Set
of tags for the test. If this AnyFreeSpec
contains no tags, this method returns an empty Map
.
This trait's implementation returns tags that were passed as strings contained in Tag
objects passed to
taggedAs
.
In addition, this trait's implementation will also auto-tag tests with class level annotations.
For example, if you annotate @Ignore
at the class level, all test methods in the class will be auto-annotated with
org.scalatest.Ignore
.
- Definition Classes
- AnyFreeSpecLike -> Suite
- Inherited from:
- AnyFreeSpecLike
An immutable Set
of test names. If this AnyFreeSpec
contains no tests, this method returns an
empty Set
.
An immutable Set
of test names. If this AnyFreeSpec
contains no tests, this method returns an
empty Set
.
This trait's implementation of this method will return a set that contains the names of all registered tests. The set's
iterator will return those names in the order in which the tests were registered. Each test's name is composed
of the concatenation of the text of each surrounding describer, in order from outside in, and the text of the
example itself, with all components separated by a space. For example, consider this AnyFreeSpec
:
import org.scalatest.freespec.AnyFreeSpec class StackSpec extends AnyFreeSpec { "A Stack" - { "when not empty" - { "must allow me to pop" in {} } "when not full" - { "must allow me to push" in {} } } }
Invoking testNames
on this AnyFreeSpec
will yield a set that contains the following
two test name strings:
"A Stack when not empty must allow me to pop" "A Stack when not full must allow me to push"
- Definition Classes
- AnyFreeSpecLike -> Suite
- Inherited from:
- AnyFreeSpecLike
- Definition Classes
- TripleEquals -> TripleEqualsSupport
- Inherited from:
- TripleEquals
Executes the block of code passed as the second parameter, and, if it
completes abruptly with a ModifiableMessage
exception,
prepends the "clue" string passed as the first parameter to the beginning of the detail message
of that thrown exception, then rethrows it. If clue does not end in a white space
character, one space will be added
between it and the existing detail message (unless the detail message is
not defined).
Executes the block of code passed as the second parameter, and, if it
completes abruptly with a ModifiableMessage
exception,
prepends the "clue" string passed as the first parameter to the beginning of the detail message
of that thrown exception, then rethrows it. If clue does not end in a white space
character, one space will be added
between it and the existing detail message (unless the detail message is
not defined).
This method allows you to add more information about what went wrong that will be reported when a test fails. Here's an example:
withClue("(Employee's name was: " + employee.name + ")") { intercept[IllegalArgumentException] { employee.getTask(-1) } }
If an invocation of intercept
completed abruptly with an exception, the resulting message would be something like:
(Employee's name was Bob Jones) Expected IllegalArgumentException to be thrown, but no exception was thrown
- Throws:
- NullArgumentException
if the passed
clue
isnull
- Inherited from:
- Assertions
Run the passed test function in the context of a fixture established by this method.
Run the passed test function in the context of a fixture established by this method.
This method should set up the fixture needed by the tests of the
current suite, invoke the test function, and if needed, perform any clean
up needed after the test completes. Because the NoArgTest
function
passed to this method takes no parameters, preparing the fixture will require
side effects, such as reassigning instance var
s in this Suite
or initializing
a globally accessible external database. If you want to avoid reassigning instance var
s
you can use FixtureSuite.
This trait's implementation of runTest
invokes this method for each test, passing
in a NoArgTest
whose apply
method will execute the code of the test.
This trait's implementation of this method simply invokes the passed NoArgTest
function.
- Value parameters:
- test
the no-arg test function to run with a fixture
- Inherited from:
- TestSuite
Deprecated and Inherited methods
- Deprecated
- Definition Classes
- TripleEquals -> TripleEqualsSupport
- Inherited from:
- TripleEquals
- Deprecated
- Definition Classes
- TripleEquals -> TripleEqualsSupport
- Inherited from:
- TripleEquals
- Deprecated
- Definition Classes
- TripleEquals -> TripleEqualsSupport
- Inherited from:
- TripleEquals
- Deprecated
- Definition Classes
- TripleEquals -> TripleEqualsSupport
- Inherited from:
- TripleEquals
Trap and return any thrown exception that would normally cause a ScalaTest test to fail, or create and return a new RuntimeException
indicating no exception is thrown.
Trap and return any thrown exception that would normally cause a ScalaTest test to fail, or create and return a new RuntimeException
indicating no exception is thrown.
This method is intended to be used in the Scala interpreter to eliminate large stack traces when trying out ScalaTest assertions and
matcher expressions. It is not intended to be used in regular test code. If you want to ensure that a bit of code throws an expected
exception, use intercept
, not trap
. Here's an example interpreter session without trap
:
scala> import org.scalatest._ import org.scalatest._ scala> import Matchers._ import Matchers._ scala> val x = 12 a: Int = 12 scala> x shouldEqual 13 org.scalatest.exceptions.TestFailedException: 12 did not equal 13 at org.scalatest.Assertions$class.newAssertionFailedException(Assertions.scala:449) at org.scalatest.Assertions$.newAssertionFailedException(Assertions.scala:1203) at org.scalatest.Assertions$AssertionsHelper.macroAssertTrue(Assertions.scala:417) at .<init>(<console>:15) at .<clinit>(<console>) at .<init>(<console>:7) at .<clinit>(<console>) at $print(<console>) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at scala.tools.nsc.interpreter.IMain$ReadEvalPrint.call(IMain.scala:731) at scala.tools.nsc.interpreter.IMain$Request.loadAndRun(IMain.scala:980) at scala.tools.nsc.interpreter.IMain.loadAndRunReq$1(IMain.scala:570) at scala.tools.nsc.interpreter.IMain.interpret(IMain.scala:601) at scala.tools.nsc.interpreter.IMain.interpret(IMain.scala:565) at scala.tools.nsc.interpreter.ILoop.reallyInterpret$1(ILoop.scala:745) at scala.tools.nsc.interpreter.ILoop.interpretStartingWith(ILoop.scala:790) at scala.tools.nsc.interpreter.ILoop.command(ILoop.scala:702) at scala.tools.nsc.interpreter.ILoop.processLine$1(ILoop.scala:566) at scala.tools.nsc.interpreter.ILoop.innerLoop$1(ILoop.scala:573) at scala.tools.nsc.interpreter.ILoop.loop(ILoop.scala:576) at scala.tools.nsc.interpreter.ILoop$$anonfun$process$1.apply$mcZ$sp(ILoop.scala:867) at scala.tools.nsc.interpreter.ILoop$$anonfun$process$1.apply(ILoop.scala:822) at scala.tools.nsc.interpreter.ILoop$$anonfun$process$1.apply(ILoop.scala:822) at scala.tools.nsc.util.ScalaClassLoader$.savingContextLoader(ScalaClassLoader.scala:135) at scala.tools.nsc.interpreter.ILoop.process(ILoop.scala:822) at scala.tools.nsc.MainGenericRunner.runTarget$1(MainGenericRunner.scala:83) at scala.tools.nsc.MainGenericRunner.process(MainGenericRunner.scala:96) at scala.tools.nsc.MainGenericRunner$.main(MainGenericRunner.scala:105) at scala.tools.nsc.MainGenericRunner.main(MainGenericRunner.scala)
That's a pretty tall stack trace. Here's what it looks like when you use trap
:
scala> trap { x shouldEqual 13 } res1: Throwable = org.scalatest.exceptions.TestFailedException: 12 did not equal 13
Much less clutter. Bear in mind, however, that if no exception is thrown by the
passed block of code, the trap
method will create a new NormalResult
(a subclass of Throwable
made for this purpose only) and return that. If the result was the Unit
value, it
will simply say that no exception was thrown:
scala> trap { x shouldEqual 12 } res2: Throwable = No exception was thrown.
If the passed block of code results in a value other than Unit
, the NormalResult
's toString
will print the value:
scala> trap { "Dude!" } res3: Throwable = No exception was thrown. Instead, result was: "Dude!"
Although you can access the result value from the NormalResult
, its type is Any
and therefore not
very convenient to use. It is not intended that trap
be used in test code. The sole intended use case for trap
is decluttering
Scala interpreter sessions by eliminating stack traces when executing assertion and matcher expressions.
- Deprecated
- Inherited from:
- Assertions
Inherited fields
Supports shared test registration in AnyFreeSpec
s.
Supports shared test registration in AnyFreeSpec
s.
This field enables syntax such as the following:
behave like nonFullStack(stackWithOneItem) ^
For more information and examples of the use of
- Inherited from:
- AnyFreeSpecLike
The Succeeded
singleton.
The Succeeded
singleton.
You can use succeed
to solve a type error when an async test
does not end in either Future[Assertion]
or Assertion
.
Because Assertion
is a type alias for Succeeded.type
,
putting succeed
at the end of a test body (or at the end of a
function being used to map the final future of a test body) will solve
the type error.
- Inherited from:
- Assertions
Deprecated and Inherited fields
The styleName
lifecycle method has been deprecated and will be removed in a future version of ScalaTest.
The styleName
lifecycle method has been deprecated and will be removed in a future version of ScalaTest.
This method was used to support the chosen styles feature, which was deactivated in 3.1.0. The internal modularization of ScalaTest in 3.2.0
will replace chosen styles as the tool to encourage consistency across a project. We do not plan a replacement for styleName
.
- Deprecated
- Inherited from:
- AnyFreeSpecLike
Extensions
Inherited extensions
Implicits
Inherited implicits
Implicitly converts String
s to FreeSpecStringWrapper
, which enables
methods in
, is
, taggedAs
and ignore
,
as well as the dash operator (-
), to be invoked on String
s.
Implicitly converts String
s to FreeSpecStringWrapper
, which enables
methods in
, is
, taggedAs
and ignore
,
as well as the dash operator (-
), to be invoked on String
s.
- Inherited from:
- AnyFreeSpecLike
- Definition Classes
- TripleEquals -> TripleEqualsSupport
- Inherited from:
- TripleEquals