Checkpoints

Trait providing class Checkpoint, which enables multiple assertions to be performed within a test, with any failures accumulated and reported together at the end of the test.

Because ScalaTest uses exceptions to signal failed assertions, normally execution of a test will stop as soon as the first failed assertion is encountered. Trait Checkpoints provides an option when you want to continue executing the remainder of the test body, or part of it, even if an assertion has already failed in that test.

To use a Checkpoint (once you've mixed in or imported the members of trait Checkpoints), you first need to create one, like this:

val cp = new Checkpoint

Then give the Checkpoint assertions to execute by passing them (via a by-name parameter) to its apply method, like this:

val (x, y) = (1, 2)
cp { x should be < 0 }
cp { y should be > 9 }

Both of the above assertions will fail, but it won't be reported yet. The Checkpoint will execute them right away, each time its apply method is invoked. But it will catch the TestFailedExceptions and save them, only reporting them later when reportAll is invoked. Thus, at the end of the test, you must call reportAll, like this:

cp.reportAll()

This reportAll invocation will complete abruptly with a TestFailedException whose message includes the message, source file, and line number of each of the checkpointed assertions that previously failed. For example:

1 was not less than 0 (in Checkpoint) at ExampleSpec.scala:12
2 was not greater than 9 (in Checkpoint) at ExampleSpec.scala:13

Make sure you invoke reportAll before the test completes, otherwise any failures that were detected by the Checkpoint will not be reported.

Note that a Checkpoint will catch and record for later reporting (via reportAll) exceptions that mix in StackDepth except for TestCanceledException, TestRegistrationClosedException, NotAllowedException, and DuplicateTestNameException. If a block of code passed to a Checkpoint's apply method completes abruptly with any of the StackDepth exceptions in the previous list, or any non-StackDepth exception, that invocation of the apply method will complete abruptly with the same exception immediately. Unless you put reportAll in a finally clause and handle this case, such an unexpected exception will cause you to lose any information about assertions that failed earlier in the test and were recorded by the Checkpoint.