normalize paths for tests

Author: Martijn Hoekstra

test/test/CompilerTest.scala

@@ -452,8 +452,7 @@ abstract class CompilerTest {
     processFileDir(sourceFile, { sf =>
       if (extensionsToCopy.contains(sf.extension)) {
         dest.parent.jfile.mkdirs
-        dest.toFile.writeAll("/* !!!!! WARNING: DO NOT MODIFY. Original is at: $sf !!!!! */",
-          sf.slurp())
+        dest.toFile.writeAll(s"/* !!!!! WARNING: DO NOT MODIFY. Original is at: $sf !!!!! */", sf.slurp)
       } else {
         log(s"WARNING: ignoring $sf")
       }

test/test/InterfaceEntryPointTest.scala

@@ -18,7 +18,7 @@ import scala.collection.mutable.ListBuffer
  */
 class InterfaceEntryPointTest {
   @Test def runCompilerFromInterface = {
-    val sources = List("./tests/pos/HelloWorld.scala")
+    val sources = List("./tests/pos/HelloWorld.scala").map(p => new java.io.File(p).getPath())
     val args = sources ++ List("-d", "./out/")
 
     val mainClass = Class.forName("dotty.tools.dotc.Main")

test/test/OtherEntryPointsTest.scala

@@ -17,7 +17,7 @@ import scala.collection.mutable.ListBuffer
  */
 class OtherEntryPointsTest {
   @Test def runCompiler = {
-    val sources = List("./tests/pos/HelloWorld.scala")
+    val sources = List("./tests/pos/HelloWorld.scala").map(p => new java.io.File(p).getPath())
     val args = sources ++ List("-d", "./out/")
 
     val reporter = new CustomReporter
@@ -31,7 +31,7 @@ class OtherEntryPointsTest {
   }
 
   @Test def runCompilerWithContext = {
-    val sources = List("./tests/pos/HelloWorld.scala")
+    val sources = List("./tests/pos/HelloWorld.scala").map(p => new java.io.File(p).getPath())
     val args = sources ++ List("-d", "./out/")
 
     val reporter = new CustomReporter