anchor.diff:      options.sdkSummary = sdkSummary;
       IncrementalCompiler compiler =
           new IncrementalKernelGenerator(options, main);
  +    Stopwatch stopwatch = new Stopwatch()..start();
       var program = await compiler.computeDelta();
  +    print("Normal compile took ${stopwatch.elapsedMilliseconds} ms");
       libCount2 = serializeProgram(program);
       if (program.libraries.length != 2) {
         throw "Expected 2 libraries, got ${program.libraries.length}";
  
positive.code: Directory outDir;
  
  main() async {
    outDir =
        Directory.systemTemp.createTempSync("incremental_load_from_dill_test");
    try {
      await testDart2jsCompile();
      await testDisappearingLibrary();
      await testDeferredLibrary();
    } finally {
      outDir.deleteSync(recursive: true);
    }
  }
  
  /// Test loading from a dill file with a deferred library.
  
negative.code:   return options;
  }
  
  Future<bool> normalCompile(Uri input, Uri output,
      {CompilerOptions options}) async {
    options ??= getOptions();
    IncrementalCompiler compiler = new IncrementalKernelGenerator(options, input);
    var y = await compiler.computeDelta();
    await writeProgramToFile(y, output);
  