Cross-build to scala 3 (#244)

* Attempt cross-build to scala 3
* Only use kind-projector plugin under scala 2
* Do not duplicate sbt-tpolecat options
* Add source 3 cross-compilation
* Add scalafmt
* Remove redundant final modifier
* Make UtilitiesTest work under scala 3 expect implementation

.github/workflows/ci.yml

@@ -27,7 +27,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        scala: [2.13.15, 2.12.20]
+        scala: [2.13.15, 2.12.20, 3.3.4]
         java: [temurin@21]
     runs-on: ${{ matrix.os }}
     steps:
@@ -50,12 +50,12 @@ jobs:
       - name: Check that workflows are up to date
         run: sbt '++ ${{ matrix.scala }}' githubWorkflowCheck
 
+      - run: sbt '++ ${{ matrix.scala }}' scalafmtCheck
+
       - env:
           HONEYCOMB_WRITE_KEY: ${{ secrets.HONEYCOMB_WRITE_KEY }}
         run: sbt '++ ${{ matrix.scala }}' test
 
-      - run: 'bash <(curl -s https://codecov.io/bash)'
-
       - name: Compress target directories
         run: tar cf targets.tar target project/target
 
@@ -112,6 +112,16 @@ jobs:
           tar xf targets.tar
           rm targets.tar
 
+      - name: Download target directories (3.3.4)
+        uses: actions/download-artifact@v4
+        with:
+          name: target-${{ matrix.os }}-3.3.4-${{ matrix.java }}
+
+      - name: Inflate target directories (3.3.4)
+        run: |
+          tar xf targets.tar
+          rm targets.tar
+
       - run: |
           git config user.name "Github Actions (dimitarg/weaver-test-extra)"
           git config user.email "[email protected]"

.scalafmt.conf

@@ -0,0 +1,3 @@
+version = 3.8.2
+runner.dialect = scala213source3
+maxColumn = 120

build.sbt

@@ -5,12 +5,15 @@ name := "weaver-test-extra"
 ThisBuild / organization := "io.github.dimitarg"
 
 ThisBuild / scalaVersion := "2.13.15"
-ThisBuild / crossScalaVersions := Seq("2.13.15", "2.12.20")
-ThisBuild / githubWorkflowScalaVersions  := Seq("2.13.15", "2.12.20")
+ThisBuild / crossScalaVersions := Seq("2.13.15", "2.12.20", "3.3.4")
+ThisBuild / githubWorkflowScalaVersions  := Seq("2.13.15", "2.12.20", "3.3.4")
 
 ThisBuild / githubWorkflowJavaVersions  := Seq(JavaSpec.temurin("21"))
 
 ThisBuild / githubWorkflowBuild := Seq(
+  WorkflowStep.Sbt(
+    commands = List("scalafmtCheck")
+  ),
   WorkflowStep.Sbt(
     // scoverage plugin not yet supporting scala 2.13.15
     // commands = List("coverage", "test"),
@@ -34,9 +37,10 @@ ThisBuild / githubWorkflowPublishTargetBranches += RefPredicate.Equals(Ref.Branc
 
 ThisBuild / licenses += ("Apache-2.0", url("https://opensource.org/licenses/Apache-2.0"))
 
-ThisBuild / githubWorkflowBuildPostamble := Seq(WorkflowStep.Run(
-  commands = List("bash <(curl -s https://codecov.io/bash)")
-))
+// scoverage plugin not yet supporting scala 2.13.15
+// ThisBuild / githubWorkflowBuildPostamble := Seq(WorkflowStep.Run(
+//   commands = List("bash <(curl -s https://codecov.io/bash)")
+// ))
 
 ThisBuild / githubWorkflowPublishPreamble := Seq(WorkflowStep.Run(
   List(
@@ -67,7 +71,23 @@ libraryDependencies ++=Seq(
 
 testFrameworks += new TestFramework("weaver.framework.CatsEffect")
 
-addCompilerPlugin("org.typelevel" % "kind-projector" % "0.13.3" cross CrossVersion.full)
+libraryDependencies ++= {
+  CrossVersion.partialVersion(scalaVersion.value) match {
+    case Some((2, n)) =>
+      List(
+        compilerPlugin("org.typelevel" % "kind-projector" % "0.13.3" cross CrossVersion.full)
+      )
+    case _ =>
+      Nil
+  }
+}
+
+ThisBuild / scalacOptions ++= {
+  CrossVersion.partialVersion(scalaVersion.value) match {
+    case Some((2, 12 | 13)) => Seq("-Xsource:3-cross", "-P:kind-projector:underscore-placeholders")
+    case _ => Nil
+  }
+}
 
 releasePublishArtifactsAction := PgpKeys.publishSigned.value
 

project/plugins.sbt

@@ -5,3 +5,4 @@ addSbtPlugin("org.typelevel" % "sbt-tpolecat" % "0.5.2")
 addSbtPlugin("com.github.sbt" % "sbt-release" % "1.4.0")
 addSbtPlugin("org.xerial.sbt" % "sbt-sonatype" % "3.12.2")
 addSbtPlugin("com.github.sbt" % "sbt-pgp" % "2.3.0")
+addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.5.2")

src/main/scala/weaver/pure/Suite.scala

@@ -16,4 +16,4 @@ trait Suite extends EffectSuite[IO] with BaseCatsSuite with Expectations.Helpers
   override implicit protected def effectCompat: EffectCompat[IO] = CatsUnsafeRun
 
   override def getSuite: EffectSuite[IO] = this
-}
+}

src/main/scala/weaver/pure/package.scala

@@ -5,17 +5,23 @@ import cats.effect.IO
 import fs2.Stream
 
 package object pure extends Expectations.Helpers {
-  
+
   import util._
 
-  def test(name: String)(run: IO[Expectations])(implicit loc: SourceLocation): IO[Test] = {
+  def test(
+      name: String
+  )(run: IO[Expectations])(implicit loc: SourceLocation): IO[Test] = {
     failureToExpectations(run)
       .map(x => Test(name, x))
   }
 
-  def pureTest(name: String)(run: => Expectations)(implicit loc: SourceLocation): Test = Test(name, run)
+  def pureTest(name: String)(run: => Expectations)(implicit
+      loc: SourceLocation
+  ): Test = Test(name, run)
 
-  def parSuite(tests: List[IO[Test]]): Stream[IO, Test] = Stream.evals(tests.parTraverse(identity))
+  def parSuite(tests: List[IO[Test]]): Stream[IO, Test] =
+    Stream.evals(tests.parTraverse(identity))
 
-  def seqSuite(tests: List[IO[Test]]): Stream[IO, Test] = Stream.evals(tests.sequence)
+  def seqSuite(tests: List[IO[Test]]): Stream[IO, Test] =
+    Stream.evals(tests.sequence)
 }

src/main/scala/weaver/pure/traced/package.scala

@@ -12,10 +12,13 @@ package object traced {
 
   type TracedTest = ReaderT[IO, Span[IO], Test]
 
-  def tracedTest(name: String)(run: Span[IO] => IO[Expectations])(implicit loc: SourceLocation): TracedTest =
+  def tracedTest(name: String)(
+      run: Span[IO] => IO[Expectations]
+  )(implicit loc: SourceLocation): TracedTest =
     ReaderT { parent =>
-      parent.span(name).use{ span =>
-        weaver.pure.test(name)(run(span))
+      parent.span(name).use { span =>
+        weaver.pure
+          .test(name)(run(span))
           .flatTap { test =>
             traceExpectationFailures(span, test)
           }
@@ -28,18 +31,24 @@ package object traced {
       _ => IO.unit
     )
 
-  def tracedParSuite(name: String)(suite: List[TracedTest])(implicit rootSpan: Span[IO]): Stream[IO,Test] =
+  def tracedParSuite(name: String)(suite: List[TracedTest])(implicit
+      rootSpan: Span[IO]
+  ): Stream[IO, Test] =
     tracedSuite(weaver.pure.parSuite)(name)(suite)(rootSpan)
-
-  def tracedSeqSuite(name: String)(suite: List[TracedTest])(implicit rootSpan: Span[IO]): Stream[IO,Test] =
+
+  def tracedSeqSuite(name: String)(suite: List[TracedTest])(implicit
+      rootSpan: Span[IO]
+  ): Stream[IO, Test] =
     tracedSuite(weaver.pure.seqSuite)(name)(suite)(rootSpan)
-
-  def tracedSuite(toStream: List[IO[Test]] => Stream[IO, Test])(name: String)(suite: List[TracedTest]): Span[IO] => Stream[IO,Test] =
-    parent => 
+
+  def tracedSuite(
+      toStream: List[IO[Test]] => Stream[IO, Test]
+  )(name: String)(suite: List[TracedTest]): Span[IO] => Stream[IO, Test] =
+    parent =>
       Stream.resource(parent.span(name)).flatMap { suiteSpan =>
         val testsWithSpan = suite.map(_.run(suiteSpan))
         toStream(testsWithSpan)
 
       }
-   
+
 }

src/main/scala/weaver/pure/util.scala

@@ -4,17 +4,20 @@ import weaver.{Test => WeaverTest, Expectations, SourceLocation, TestOutcome}
 
 import cats.effect.IO
 
-private [pure] object util {
-  def failureToExpectations(x: IO[Expectations])(implicit loc: SourceLocation): IO[Expectations] = {
+private[pure] object util {
+  def failureToExpectations(
+      x: IO[Expectations]
+  )(implicit loc: SourceLocation): IO[Expectations] = {
     x.handleErrorWith { t =>
       IO.delay(t.printStackTrace()).map { _ =>
         failure(t.toString())
       }
     }
   }
 
-  def toTestOutcome(test: Test): TestOutcome = WeaverTest.pure(test.name.name)(() => test.run)
+  def toTestOutcome(test: Test): TestOutcome =
+    WeaverTest.pure(test.name.name)(() => test.run)
 
   def outcomeToString(x: TestOutcome): String = x.formatted(TestOutcome.Verbose)
-    
+
 }

src/test/scala/com/dimitarg/example/ExampleResSuite.scala

@@ -10,40 +10,39 @@ import weaver.pure._
 
 object ExampleResSuite extends Suite {
 
-  // shared resource  
+  // shared resource
   final case class TextFile(lines: List[String])
 
   // describe how to acquire shared resource
   val sharedResource: Resource[IO, TextFile] = for {
     _ <- Resource.make(
-        IO(ExecutionContext.fromExecutorService(Executors.newCachedThreadPool()))
-    )( x =>
-        IO(x.shutdown)
-    )
+      IO(ExecutionContext.fromExecutorService(Executors.newCachedThreadPool()))
+    )(x => IO(x.shutdown))
     xs = fs2.io.readInputStream(
-        IO(getClass().getResourceAsStream("/foo.txt")),
-        1024, closeAfterUse = true
-    ) 
+      IO(getClass().getResourceAsStream("/foo.txt")),
+      1024,
+      closeAfterUse = true
+    )
     lines <- Resource.eval(
-        xs.through(fs2.text.utf8.decode).through(fs2.text.lines).compile.toList
+      xs.through(fs2.text.utf8.decode).through(fs2.text.lines).compile.toList
     )
   } yield TextFile(lines)
 
-
   // suite which uses shared resource
-  val suites: TextFile => Stream[IO, Test] = textFile => Stream(
-    pureTest("the file has one line") {
-      expect(textFile.lines.size == 1)
-    },
-    pureTest("the file has the expected content") {
-      expect(textFile.lines == List("Hello, there!"))    
-    }
-  )
+  val suites: TextFile => Stream[IO, Test] = textFile =>
+    Stream(
+      pureTest("the file has one line") {
+        expect(textFile.lines.size == 1)
+      },
+      pureTest("the file has the expected content") {
+        expect(textFile.lines == List("Hello, there!"))
+      }
+    )
 
   // construct `suitesStream` by acquiring resource and passing that to your `suite` via `flatMap`
   override def suitesStream: Stream[IO, Test] =
     Stream.resource(sharedResource).flatMap { res =>
       suites(res)
     }
-  
+
 }

src/test/scala/com/dimitarg/example/ExampleSharedResSuite.scala

@@ -10,39 +10,43 @@ final case class SharedResource(foo: FooResource, bar: BarResource)
 
 object FooSuite {
 
-  val all: FooResource => Stream[IO, Test] = foo => Stream(
-    pureTest("the foo foos") {
+  val all: FooResource => Stream[IO, Test] = foo =>
+    Stream(
+      pureTest("the foo foos") {
         expect(foo == FooResource())
-    }
-  )
+      }
+    )
 }
 
 object BarSuite {
-  val all: BarResource => Stream[IO, Test] = bar => Stream(
-    pureTest("a barsuite test") {
-      expect(bar.value == 42)
-    }
-  )
+  val all: BarResource => Stream[IO, Test] = bar =>
+    Stream(
+      pureTest("a barsuite test") {
+        expect(bar.value == 42)
+      }
+    )
 }
 
 object ExampleSharedResSuite extends Suite {
 
   val mkSharedResource: Resource[IO, SharedResource] = for {
     _ <- Resource.eval(IO.pure(println("acquiring shared resource")))
-    res <- Resource.eval(IO.pure(
-      SharedResource(FooResource(), BarResource(42))
-    ))
+    res <- Resource.eval(
+      IO.pure(
+        SharedResource(FooResource(), BarResource(42))
+      )
+    )
   } yield res
 
-  val suiteUsingAllResources: SharedResource => Stream[IO, Test] = res => Stream(
-    pureTest("some test"){
+  val suiteUsingAllResources: SharedResource => Stream[IO, Test] = res =>
+    Stream(pureTest("some test") {
       expect(res.bar.value == 42)
-  })
+    })
 
   override def suitesStream: Stream[IO, Test] =
     Stream.resource(mkSharedResource).flatMap { r =>
       suiteUsingAllResources(r) ++
-      FooSuite.all(r.foo) ++
-      BarSuite.all(r.bar)
+        FooSuite.all(r.foo) ++
+        BarSuite.all(r.bar)
     }
 }

src/test/scala/com/dimitarg/example/ExampleSuite.scala

@@ -10,7 +10,7 @@ object ExampleSuite extends Suite {
 
   override def suitesStream: Stream[IO, Test] = Stream(
     pureTest("a pure test") {
-      val x = 1  
+      val x = 1
       expect(x == 1)
     },
     pureTest("another pure test") {