Add coverage/coveralls (#29)

.github/workflows/ci.yml

@@ -54,4 +54,10 @@ jobs:
         run: sbt ++${{ matrix.scala }} githubWorkflowCheck
 
       - name: Build project
-        run: sbt ++${{ matrix.scala }} test
+        run: sbt ++${{ matrix.scala }} clean coverage test
+
+      - name: Upload coverage data to Coveralls
+        env:
+          COVERALLS_REPO_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          COVERALLS_FLAG_NAME: Scala ${{ matrix.scala }}
+        run: sbt ++${{ matrix.scala }} coverageReport coverageAggregate coveralls

build.sbt

@@ -70,3 +70,19 @@ developers := List(
 
 // Disable publish for now
 ThisBuild / githubWorkflowPublishTargetBranches := Seq()
+
+ThisBuild / githubWorkflowBuild := Seq(
+  WorkflowStep.Sbt(List("clean", "coverage", "test"), name = Some("Build project"))
+)
+
+ThisBuild / githubWorkflowBuildPostamble ++= Seq(
+  // See https://github.com/scoverage/sbt-coveralls#github-actions-integration
+  WorkflowStep.Sbt(
+    List("coverageReport", "coverageAggregate", "coveralls"),
+    name = Some("Upload coverage data to Coveralls"),
+    env = Map(
+      "COVERALLS_REPO_TOKEN" -> "${{ secrets.GITHUB_TOKEN }}",
+      "COVERALLS_FLAG_NAME"  -> "Scala ${{ matrix.scala }}"
+    )
+  )
+)

project/plugins.sbt

@@ -1,3 +1,5 @@
 addSbtPlugin("de.heikoseeberger" % "sbt-header"         % "5.6.0")
 addSbtPlugin("com.codecommit"    % "sbt-github-actions" % "0.14.2")
 addSbtPlugin("org.scalameta"     % "sbt-scalafmt"       % "2.4.6")
+addSbtPlugin("org.scoverage"     % "sbt-scoverage"      % "1.9.3")
+addSbtPlugin("org.scoverage"     % "sbt-coveralls"      % "1.3.1")