Fix 1336: Discard reporter output for tests that succeed.

Author: nicolasstucki

test/test/CompilerTest.scala

@@ -1,8 +1,10 @@
 package test
 
+import dotty.tools.dotc.core.Contexts._
 import dotty.partest.DPConfig
 import dotty.tools.dotc.{Main, Bench, Driver}
-import dotty.tools.dotc.reporting.Reporter
+import dotty.tools.dotc.interfaces.Diagnostic.ERROR
+import dotty.tools.dotc.reporting._
 import dotty.tools.dotc.util.SourcePosition
 import dotty.tools.dotc.config.CompilerCommand
 import dotty.tools.io.PlainFile
@@ -12,8 +14,6 @@ import scala.tools.partest.nest.{ FileManager, NestUI }
 import scala.annotation.tailrec
 import java.io.{ RandomAccessFile, File => JFile }
 
-import org.junit.Test
-
 
 /** This class has two modes: it can directly run compiler tests, or it can
   * generate the necessary file structure for partest in the directory
@@ -234,7 +234,22 @@ abstract class CompilerTest {
       (implicit defaultOptions: List[String]): Unit = {
     val allArgs = args ++ defaultOptions
     val processor = if (allArgs.exists(_.startsWith("#"))) Bench else Main
-    val reporter = processor.process(allArgs)
+    val storeReporter = new Reporter with UniqueMessagePositions with HideNonSensicalMessages {
+      private val consoleReporter = new ConsoleReporter()
+      private var innerStoreReporter = new StoreReporter(consoleReporter)
+      def doReport(d: Diagnostic)(implicit ctx: Context): Unit = {
+        if (innerStoreReporter == null) {
+          consoleReporter.report(d)
+        } else {
+          innerStoreReporter.report(d)
+          if (d.level == ERROR) {
+            innerStoreReporter.flush()
+            innerStoreReporter = null
+          }
+        }
+      }
+    }
+    val reporter = processor.process(allArgs, storeReporter)
 
     val nerrors = reporter.errorCount
     val xerrors = (expectedErrorsPerFile map {_.totalErrors}).sum
@@ -244,7 +259,7 @@ abstract class CompilerTest {
       }
     assert(nerrors == xerrors,
       s"""Wrong # of errors. Expected: $xerrors, found: $nerrors
-         |Files with expected errors: $expectedErrorFiles%, %
+         |Files with expected errors: $expectedErrorFiles
        """.stripMargin)
     // NEG TEST
     if (xerrors > 0) {