Fix #1369 Print a newline after interpreted commands

Added ScriptedTests which keep the original output and input instead of
cutting end of line whitespaces
Added a test case for Unit

Author: benkobalog

compiler/src/dotty/tools/repl/ReplDriver.scala

@@ -196,7 +196,7 @@ class ReplDriver(settings: Array[String],
         val newState = compile(parsed)
           .withHistory(parsed.sourceCode :: state.history)
           .newRun(compiler, rootCtx)
-        out.println() // Prints newline after commands, also fixes #1369
+        out.println("") // Prints newline after commands, also fixes #1369
         newState
 
       case SyntaxErrors(src, errs, _) =>

compiler/test-resources/repl-whitespace-sensitive/renderUnit

@@ -0,0 +1,6 @@
+scala> () // The test runner also adds a newline that's why there is one more newline in this test
+
+
+scala> (); (); ();
+
+

compiler/test/dotty/tools/repl/ScriptedTests.scala

@@ -20,7 +20,15 @@ class ScriptedTests extends ReplTest with MessageRendering {
     dir.listFiles
   }
 
-  private def testFile(f: JFile): Unit = {
+  def filterEmpties(line: String): List[String] =
+    line.replaceAll("""(?m)\s+$""", "") match {
+      case "" => Nil
+      case nonEmptyLine => nonEmptyLine :: Nil
+    }
+
+  def noChange(line: String): List[String] = List(line)
+
+  private def testFile(changeLines: String => List[String])(f: JFile): Unit = {
     val prompt = "scala>"
     val lines = Source.fromFile(f).getLines.buffered
 
@@ -53,14 +61,9 @@ class ScriptedTests extends ReplTest with MessageRendering {
           throw ex
       }
 
-    def filterEmpties(line: String): List[String] =
-      line.replaceAll("""(?m)\s+$""", "") match {
-        case "" => Nil
-        case nonEmptyLine => nonEmptyLine :: Nil
-      }
 
     val expectedOutput =
-      Source.fromFile(f).getLines.flatMap(filterEmpties).mkString("\n")
+      Source.fromFile(f).getLines.flatMap(changeLines).mkString("\n")
     val actualOutput = {
       resetToInitial()
       init()
@@ -71,7 +74,7 @@ class ScriptedTests extends ReplTest with MessageRendering {
         buf.append(out)
         nstate
       }
-      buf.flatMap(filterEmpties).mkString("\n")
+      buf.flatMap(changeLines).mkString("\n")
     }
 
     if (expectedOutput != actualOutput) {
@@ -84,7 +87,9 @@ class ScriptedTests extends ReplTest with MessageRendering {
     }
   }
 
-  @Test def replTests = scripts("/repl").foreach(testFile)
+  @Test def replTests = scripts("/repl").foreach(testFile(filterEmpties))
+
+  @Test def replWhitespaceTests = scripts("/repl-whitespace-sensitive").foreach(testFile(noChange))
 
-  @Test def typePrinterTests = scripts("/type-printer").foreach(testFile)
+  @Test def typePrinterTests = scripts("/type-printer").foreach(testFile(filterEmpties))
 }