Helper class used by code generated by the assert
macro.
Helper class used by code generated by the assert
macro.
Helper class used by code generated by the overriden assert
macro.
Helper class used by code generated by the overriden assert
macro.
Assert that a boolean condition, described in String
message
, is true.
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 the
String
obtained by invoking toString
on the
specified clue
as the exception's detail message and a
diagram showing expression values.
If multi-line Boolean
is passed in, it will fallback to the macro implementation of Assertions
that does not contain diagram.
the boolean condition to assert
An objects whose toString
method returns a message to include in a failure report.
NullPointerException
if message
is null
.
TestFailedException
if the condition is false
.
Assert that a boolean condition is true.
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 that includes a diagram showing expression values.
If multi-line Boolean
is passed in, it will fallback to the macro implementation of Assertions
that does not contain diagram.
the boolean condition to assert
TestFailedException
if the condition is false
.
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.
the snippet of code that should compile
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
.
the snippet of code that should not type check
Assert that the value passed as expected
equals the value passed as actual
.
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.
the expected value
the actual value, which should equal the passed expected
value
TestFailedException
if the passed actual
value does not equal the passed expected
value.
Assert that the value passed as expected
equals the value passed as actual
.
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
.
the expected value
An object whose toString
method returns a message to include in a failure report.
the actual value, which should equal the passed expected
value
TestFailedException
if the passed actual
value does not equal the passed expected
value.
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
.
the snippet of code that should not type check
Helper instance used by code generated by macro assertion.
Helper instance used by code generated by macro assertion.
Assume that a boolean condition, described in String
message
, is true.
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 the
String
obtained by invoking toString
on the
specified clue
as the exception's detail message and a
diagram showing expression values.
If multi-line Boolean
is passed in, it will fallback to the macro implementation of Assertions
that does not contain diagram.
the boolean condition to assume
An objects whose toString
method returns a message to include in a failure report.
NullPointerException
if message
is null
.
TestCanceledException
if the condition is false
.
Assume that a boolean condition is true.
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 that includes a diagram showing expression values.
If multi-line Boolean
is passed in, it will fallback to the macro implementation of Assertions
that does not contain diagram.
the boolean condition to assume
TestCanceledException
if the condition is false
.
Throws TestCanceledException
, with the passed
Throwable
cause, to indicate a test failed.
Throws TestCanceledException
, with the passed
Throwable
cause, to indicate a test failed.
The getMessage
method of the thrown TestCanceledException
will return cause.toString
.
a Throwable
that indicates the cause of the cancellation.
NullPointerException
if cause
is null
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.
A message describing the failure.
A Throwable
that indicates the cause of the failure.
NullPointerException
if message
or cause
is null
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.
A message describing the cancellation.
NullPointerException
if message
is null
Throws TestCanceledException
to indicate a test was canceled.
Throws TestCanceledException
to indicate a test was canceled.
Helper instance used by code generated by the overriden macro assertion.
Throws TestFailedException
, with the passed
Throwable
cause, to indicate a test failed.
Throws TestFailedException
, with the passed
Throwable
cause, to indicate a test failed.
The getMessage
method of the thrown TestFailedException
will return cause.toString
.
a Throwable
that indicates the cause of the failure.
NullPointerException
if cause
is null
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.
A message describing the failure.
A Throwable
that indicates the cause of the failure.
NullPointerException
if message
or cause
is null
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.
A message describing the failure.
NullPointerException
if message
is null
Throws TestFailedException
to indicate a test failed.
Throws TestFailedException
to indicate a test failed.
Intercept and return an exception that's expected to be thrown by the passed function value.
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
.
the function value that should throw the expected exception
an implicit ClassTag
representing the type of the specified
type parameter.
the intercepted exception, if it is of the expected type
TestFailedException
if the passed function does not complete abruptly with an exception
that's an instance of the specified type
passed expected
value.
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.
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.
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
NullPointerException
if the passed clue
is null
Sub-trait of
Assertions
that overrideassert
andassume
methods to include a diagram showing the values of expression in the error message when the assertion or assumption fails.Here are some examples:
If the expression passed to
assert
orassume
spans more than one line,DiagrammedAssertions
falls back to the default style of error message, since drawing a diagram would be difficult. Here's an example showing howDiagrammedAssertions
will treat a multi-line assertion (i.e., you don't get a diagram):Also, since an expression diagram essentially represents multi-line ascii art, if a clue string is provided, it appears above the diagram, not after it. It will often also show up in the diagram:
Trait
DiagrammedAssertions
was inspired by Peter Niederwieser's work in Spock and Expecty.