Skip Pitest task execution test when source set is empty

[davidburstrom]

For a regular Gradle test task from the Java plugin, if there is no test source, it will just be skipped indicating NO-SOURCE. In contrast, Pitest tasks will fail with Coverage generation minion exited abnormally. I propose that the Pitest tasks should behave similarly as the test task. As for backwards compatibility, this would cause e.g. CI builds that are currently failing to pass instead, but I have a hard time seeing that as a problem.

The current workaround I use is pretty hard-coded (and deals with configuration caching, hence it looks a little weird):

tasks.named<PitestTask>("pitest").configure {
  inputs.property("src", file("src/test"))
  onlyIf {
    (inputs.properties.get("src") as File).exists()
  }
}

[szpak]

It sounds sensible. Currently the plugin is applied only on subprojects with the Java plugin, but no test source in fact could lead to that behavior. Nevertheless, in a corner case, there could be only some test content attached from some other subprojects (e.g. with the acceptance tests).

gradle-pitest-plugin/src/main/groovy/info/solidsoft/gradle/pitest/PitestPlugin.groovy

Lines 175 to 182 in c54467b

	task.additionalClasspath.setFrom({
	List<FileCollection> testRuntimeClasspath = (extension.testSourceSets.get() as Set<SourceSet>)*.runtimeClasspath
	FileCollection combinedTaskClasspath = project.objects.fileCollection().from(testRuntimeClasspath)
	FileCollection filteredCombinedTaskClasspath = combinedTaskClasspath.filter { File file ->
	!extension.fileExtensionsToFilter.getOrElse([]).find { extension -> file.name.endsWith(".$extension") }
	} + project.files(allMutableCodePaths)
	return filteredCombinedTaskClasspath
	} as Callable<FileCollection>)

Do you think that checking if additionalClasspath has some entries would be sufficient? Or you have some better proposal?

[szpak]

Btw, it is slightly related to #292 (in terms of behavior).

[davidburstrom]

The additionalClasspath has entries from the main source set (which for all practical purposes definitely should have entries) as well as test runtime classpath elements, so that won't work.

I was thinking that it should be sufficient to check if project.objects.fileCollection().from(extensions.testSourceSets.get() as Set<SourceSet>)*.allSource) is non-empty, but haven't verified that theory.

[szpak]

Yes, testRuntimeClasspath extends the main classpath.

Maybe, but source sets were always somehow specific for me and it would have to be verified :-).

[davidburstrom]

It is of course true that the test classpath can contain the test cases, imported from another project. I'm not sure if that is a sufficiently common case...

Using @SkipWhenEmpty @InputFiles on a property populated accordingly should result in a NO-SOURCE status. Not that it's critical that the status is the same as for a Test task.

Gradle Test solves it by having a testClassesDirs property which is separate from the test runtime classpath.

[esfomeado]

Any plans of when this would be available.

So far I have to exclude certain modules from running the pitest task.