Add test case for issue #247

src/test/scala/scala/compat/java8/Issue247Test.scala

@@ -0,0 +1,83 @@
+/*
+ * Scala (https://www.scala-lang.org)
+ *
+ * Copyright EPFL and Lightbend, Inc.
+ *
+ * Licensed under Apache License 2.0
+ * (http://www.apache.org/licenses/LICENSE-2.0).
+ *
+ * See the NOTICE file distributed with this work for
+ * additional information regarding copyright ownership.
+ */
+
+package scala.compat.java8
+
+import org.junit.Assert._
+import org.junit.Assume.assumeTrue
+import org.junit.Test
+import org.junit.function.ThrowingRunnable
+
+import java.nio.file.{Files, Paths}
+import scala.compat.java8.StreamConverters._
+import scala.compat.java8.issue247.Main
+import scala.sys.process._
+import scala.util.Try
+
+class Issue247Test {
+  @Test
+  def runMainDirectly(): Unit = Main.main(Array.empty)
+
+  val mainCls = "scala.compat.java8.issue247.Main"
+
+  @Test
+  def runMainMatrix(): Unit = {
+    assumeTrue("only run in Linux/OSX", "which which".! == 0)
+
+    val pwd = "pwd".!!.trim
+
+    val coursier = Try {
+      ("which cs" #|| "which coursier").!!.trim
+    }.getOrElse {
+      val cs = s"$pwd/target/coursier"
+      if (!Files.isExecutable(Paths.get(cs)))
+        ( s"curl -fLo $cs https://git.io/coursier-cli" #&&
+          s"chmod +x $cs"
+        ).!.ensuring(_ == 0)
+      cs
+    }
+
+    for {
+      scalaBinV <- Seq("2.11", "2.12", "2.13", "3")
+      compatV <- Seq("0.9.1", "1.0.0", "1.0.1")
+      // scala-java8-compat for scala3 don't have version 0.9.1
+      if scalaBinV != "3" || compatV != "0.9.1"
+      scalaDir <- Files.list(Paths.get(pwd, "target")).toScala[List]
+      if scalaDir.toFile.getName.startsWith(s"scala-$scalaBinV")
+      classesDir = scalaDir.resolve("test-classes")
+      if classesDir.resolve("scala/compat/java8/issue247/Main.class").toFile.isFile
+    } {
+      val classpath = Process(
+        Seq(
+          coursier, // may contain spaces
+          "fetch", "--classpath",
+          s"org.scala-lang.modules:scala-java8-compat_$scalaBinV:$compatV"
+        )
+      ).!!.trim
+
+      val testCmd = s"java -cp $classpath:$classesDir $mainCls"
+
+      val run: ThrowingRunnable = new ThrowingRunnable {
+        def run(): Unit = {
+          println(testCmd)
+          testCmd.!!
+        }
+      }
+
+      if ((scalaBinV, compatV) == ("2.13", "0.9.1")) {
+        run.run() // no Exception
+      } else {
+        assertThrows(classOf[RuntimeException], run)
+      }
+    }
+  }
+}

src/test/scala/scala/compat/java8/issue247/Main.scala

@@ -0,0 +1,27 @@
+/*
+ * Scala (https://www.scala-lang.org)
+ *
+ * Copyright EPFL and Lightbend, Inc.
+ *
+ * Licensed under Apache License 2.0
+ * (http://www.apache.org/licenses/LICENSE-2.0).
+ *
+ * See the NOTICE file distributed with this work for
+ * additional information regarding copyright ownership.
+ */
+
+package scala.compat.java8.issue247
+
+import scala.compat.java8.FunctionConverters._
+import java.util.function.IntFunction
+
+object Main {
+  def invoke(jfun: IntFunction[String]): String = jfun(2)
+
+  def main(args: Array[String]): Unit = {
+    val sfun = (i: Int) => s"ret: $i"
+    val ret = invoke(sfun.asJava)
+    assert(ret == "ret: 2")
+    println(s"OK. $ret")
+  }
+}