anchor.diff:  
             outputParser.expectSources = false;
             streamController.add('compile-expression-to-js abc\n'
  -                  '$library\n1\n1\nabc\nabc\n$module\n2+2\n'
  +                  '$library\n2\n1\nabc\nabc\n$module\n2+2\n'
                 .codeUnits);
             count += 1;
           } else if (count == 2) {
  
positive.code:     final platformKernel =
          computePlatformBinariesLocation().resolve('vm_platform_strong.dill');
      final ddcPlatformKernel =
          computePlatformBinariesLocation().resolve('ddc_sdk.dill');
      final sdkRoot = computePlatformBinariesLocation();
  
  
negative.code: 
      test('compile expression', () async {
        var file = File('${tempDir.path}/foo.dart')..createSync();
        file.writeAsStringSync("main() {\n}\n");
        var dillFile = File('${tempDir.path}/app.dill');
  
        var package_config =
            File('${tempDir.path}/.dart_tool/package_config.json')
              ..createSync(recursive: true)
              ..writeAsStringSync('''
    {
      "configVersion": 2,
      "packages": [
        {
          "name": "hello",
          "rootUri": "../",
          "packageUri": "./"
        }
      ]
    }
    ''');
  
        expect(dillFile.existsSync(), equals(false));
        final List<String> args = <String>[
          '--sdk-root=${sdkRoot.toFilePath()}',
          '--incremental',
          '--platform=${platformKernel.path}',
          '--output-dill=${dillFile.path}',
          '--packages=${package_config.path}',
        ];
  
        final StreamController<List<int>> streamController =
  