Add tests fixing #1322

Author: felixmulder

test/scripts/TestDotc.scala

@@ -0,0 +1,89 @@
+package test
+
+import org.junit.Assert._
+import org.junit.{Before, After, Test}
+
+import scala.io.Source
+import scala.sys.process.{Process, ProcessLogger}
+import java.io.{File => JFile, FileNotFoundException}
+
+class TestDotc {
+  private val lineSep = util.Properties.lineSeparator
+  private def doUnlessWindows(op: => Unit) =
+    if (!System.getProperty("os.name").toLowerCase.contains("windows"))
+      op
+    else
+      Console.err.println("[warn] Could not perform test, windows batch-scripts not available")
+
+  private def executeScript(script: String): (Int, String) = {
+    val sb = new StringBuilder
+    val ret = Process(script) ! ProcessLogger(sb append _)
+    (ret, sb.toString)
+  }
+
+  private def deletePackages: Unit = {
+    def delete(path: String) = {
+      val file = new JFile(path)
+      if (file.exists) file.delete()
+    }
+
+    try {
+      for (jar <- Source.fromFile(".packages").getLines())
+        delete(jar)
+
+      delete(".packages")
+      delete("src/dotty/tools/dotc/Dummy.scala")
+    } catch {
+      case _: FileNotFoundException => ()
+    }
+  }
+
+  @Before def buildUp  = deletePackages
+  @After  def tearDown = deletePackages
+
+  /** bin/dotc script should be able to build hello world and successfully
+   *  execute it using dotr
+   */
+  @Test def buildAndRunHelloWorld = doUnlessWindows {
+    val (retDotc, dotcOutput) = executeScript("bin/dotc tests/pos/HelloWorld.scala")
+
+    // Check correct output of building and running dotc
+    assert(
+      retDotc == 0,
+      s"bin/dotc script did not run properly. Output:$lineSep$dotcOutput"
+    )
+
+    val (retDotr, dotrOutput) = executeScript("bin/dotr HelloWorld")
+    assert(
+      retDotr == 0 && dotrOutput == "hello world",
+      s"Running hello world exited with status: $retDotr and output: $dotrOutput"
+    )
+  }
+
+  /** bin/dotc script should be able to detect changes in dotty sources and
+   *  rebuild dotty if needed
+   */
+  @Test def rebuildIfNecessary = doUnlessWindows {
+    val (retFirstBuild, _) = executeScript("bin/dotc tests/pos/HelloWorld.scala")
+    assert(retFirstBuild == 0, "building dotc failed")
+
+    // Create a new file
+    new JFile("src/dotty/tools/dotc/Dummy.scala").createNewFile()
+
+    val (retSecondBuild, output) = executeScript("bin/dotc tests/pos/HelloWorld.scala")
+    assert(
+      retSecondBuild == 0 && output.contains("rebuilding"),
+      s"Rebuilding the tool should result in jar files being rebuilt. Status: $retSecondBuild, output:$lineSep$output")
+  }
+
+  /** if no changes to dotty, dotc script should be fast */
+  @Test def beFastOnNoChanges = doUnlessWindows {
+    val (retFirstBuild, _) = executeScript("bin/dotc tests/pos/HelloWorld.scala")
+    assert(retFirstBuild == 0, "building dotc failed")
+
+    val (ret, output) = executeScript("bin/dotc tests/pos/HelloWorld.scala")
+    assert(
+      ret == 0 && !output.contains("rebuilding"),
+      s"Project recompiled when it didn't need to be. Status $ret, output:$lineSep$output")
+  }
+}