Make TestExecutionSummary.Failure serializable

[loicmathieu]

Overview

Make the TestExecutionSummary.Failure interface serializable.

The Throwable and TestIdentifier classes that are used by this interface are serializable, so it is safe to make it serializable also.

The default implementation org.junit.platform.launcher.listeners.MutableTestExecutionSummary.DefaultFailure is also safe to make serializable as it's a simple Java Bean with these two serializable fields.

I need to be able to serialize to disk the failures of a test for QuickPerf, a tool that I works on a JUnit5 implementation that allows to make rapid performance test with JUnit4 and soon 5.

As QuickPerf needs to launch a test in a separate JVM we need a way to pass the failures from one JVM to the other, and serializing them to disk is the easiest way to do it.

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I hereby agree to the terms of the JUnit Contributor License Agreement.

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Definition of Done

• ❌ Change is covered by automated tests including corner cases, errors, and exception handling
• Change is documented in the User Guide and Release Notes
• All continuous integration builds pass

[sbrannen]

Thanks for the PR!

Tentatively slated for 5.6 M2 for team discussion ...

[marcphilipp]

Team Decision: Let's do it.

[sbrannen]

This has been merged into master.

Thanks