Don't use 'interface' in test files.

editor/tools/plugins/com.google.dart.tools.core_test/src/com/google/dart/tools/core/internal/model/testsource/SpreadArgumentTest.dart

Index: editor/tools/plugins/com.google.dart.tools.core_test/src/com/google/dart/tools/core/internal/model/testsource/SpreadArgumentTest.dart
diff --git a/editor/tools/plugins/com.google.dart.tools.core_test/src/com/google/dart/tools/core/internal/model/testsource/SpreadArgumentTest.dart b/editor/tools/plugins/com.google.dart.tools.core_test/src/com/google/dart/tools/core/internal/model/testsource/SpreadArgumentTest.dart
deleted file mode 100644
index 3187878b9b0abd46ef80537ec7b9b6417f4db9ac..0000000000000000000000000000000000000000
--- a/editor/tools/plugins/com.google.dart.tools.core_test/src/com/google/dart/tools/core/internal/model/testsource/SpreadArgumentTest.dart
+++ /dev/null
@@ -1,46 +0,0 @@
-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-class A {
-  A() {}
-  bar(a, b, c) {
-    assert(a == 10);
-    assert(b == 11);
-    assert(c == 12);
-    return 0;
-  }
-}
-
-class SpreadArgumentTest extends A {
-  SpreadArgumentTest() : super() {}
-
-  int bar(a, b, c) {
-    assert(a == 0);
-    assert(b == 1);
-    assert(c == 2);
-    return 1;
-  }
-
-  void superBar(mode) {
-    if (mode == 0) {
-      return super.bar(10, 11, ... [12]);
-    } else {
-      return super.bar(...[10, 11, 12]);
-    }
-  }
-
-  static void main(args) {
-    var test = new SpreadArgumentTest();
-    var a = [1, 2];
-    var b = [0, 1, 2];
-    var returnValue = test.bar(0, ...a);
-    assert(returnValue == 1);
-    returnValue = test.bar(... b);
-    assert(returnValue == 1);
-    returnValue = test.superBar(0);
-    assert(returnValue == 0);
-    returnValue = test.superBar(1);
-    assert(returnValue == 0);
-  }
-}