Excluding tests from coverage report with sbt coverage

Question

I have a test that is non-functional, so I do not want it to affect the coverage report. Other than putting it in a separate project, is there a way to exclude it from the report when running

sbt clean coverage test coverageReport

As it stands, it is obscuring missing coverage by other tests.

To explain better I've made a sample project in GitHub. There are two test classes - MainSpec and DoubleSpec. I've commented out the test in DoubleSpec to show that the test in MainSpec gives 100% coverage. However, it's obscuring that DoubleSpec is "broken". MainSpec is not testing the functionality, only checking the return type.

The example is contrived. I have a much more complex example which I cannot share.

I've tried using coverageExcludedFiles but this only excludes source from coverage, not tests.

Answer 1

Consider creating a ScalaTest tag

import org.scalatest.Tag
object ExcludeFromCoverage extends Tag("ExcludeFromCoverage")

based on which to exclude particular tests only when running coverage

  "double" should "return an Int" taggedAs ExcludeFromCoverage in {
    ...
  }

so now executing using testOnly like so

sbt clean coverage  "testOnly * -- -l ExcludeFromCoverage" coverageReport

will exclude "double" should "return an Int" from the coverage report. Note you can still execute all tests with sbt test.

---

Given above, then to still run tests tagged with ExcludeFromCoverage but not include them in coverage consider defining a custom command like so

commands += Command.command("testWithSmartCoverage") { state =>
  "clean" :: 
  "set coverageEnabled := true" :: 
  "testOnly * -- -l ExcludeFromCoverage" :: 
  "set coverageEnabled := false" ::
  "testOnly * -- -n ExcludeFromCoverage" :: 
  "coverageReport" :: 
  state
}