Adds targets to a mill.scalalib.ScalaModule to create test coverage reports.

This module allows you to generate code coverage reports for Scala projects with Scoverage via the scoverage compiler plugin.

To declare a module for which you want to generate coverage reports you can extend the mill.contrib.scoverage.ScoverageModule trait when defining your Module. Additionally, you must define a submodule that extends the ScoverageTests trait that belongs to your instance of ScoverageModule.

// You have to replace VERSION
import $ivy.`com.lihaoyi::mill-contrib-buildinfo:VERSION`
import mill.contrib.scoverage.ScoverageModule

Object foo extends ScoverageModule  {
  def scalaVersion = "2.13.15"
  def scoverageVersion = "2.1.1"

  object test extends ScoverageTests {
    def ivyDeps = Agg(ivy"org.scalatest::scalatest:3.2.19")
    def testFrameworks = Seq("org.scalatest.tools.Framework")
  }
}

In addition to the normal tasks available to your Scala module, Scoverage Modules introduce a few new tasks and changes the behavior of an existing one.

- mill foo.scoverage.compile # compiles your module with test instrumentation # (you don't have to run this manually, running the test task will force its invocation)

- mill foo.test # tests your project and collects metrics on code coverage - mill foo.scoverage.htmlReport # uses the metrics collected by a previous test run to generate a coverage report in html format - mill foo.scoverage.xmlReport # uses the metrics collected by a previous test run to generate a coverage report in xml format

The measurement data by default is available at out/foo/scoverage/dataDir.dest/, the html report is saved in out/foo/scoverage/htmlReport.dest/, and the xml report is saved in out/foo/scoverage/xmlReport.dest/.