anchor.diff:    environment["updateExpectations"] =
         const String.fromEnvironment("updateExpectations");
     return ClosureConversionContext.create(suite, environment);
  -}
  -
  -class FastaCompile
  -    extends Step<TestDescription, Program, ClosureConversionContext> {
  -  const FastaCompile();
  -
  -  String get name => "fasta compilation";
  -
  -  Future<Result<Program>> run(
  -      TestDescription description, ClosureConversionContext context) async {
  -    Program platform = await context.loadPlatform();
  -    Ticker ticker = new Ticker();
  -    DillTarget dillTarget = new DillTarget(ticker, context.uriTranslator,
  -        new VmFastaTarget(new TargetFlags(strongMode: context.strongMode)));
  -    platform.unbindCanonicalNames();
  -    dillTarget.loader.appendLibraries(platform);
  -    KernelTarget sourceTarget = new KernelTarget(
  -        PhysicalFileSystem.instance, dillTarget, context.uriTranslator);
  -
  -    Program p;
  -    try {
  -      sourceTarget.read(description.uri);
  -      await dillTarget.buildOutlines();
  -      await sourceTarget.buildOutlines();
  -      p = await sourceTarget.buildProgram();
  -    } on deprecated_InputError catch (e, s) {
  -      return fail(null, e.error, s);
  -    }
  -    return pass(p);
  -  }
   }
   
   class ArgumentExtraction
  
positive.code:           // TODO(29143): add `Run` step when Vectors are added to VM.
          ];
  
    Future<Program> loadPlatform() async {
      Uri sdk = await computePatchedSdk();
      return loadProgramFromBinary(sdk.resolve('platform.dill').toFilePath());
    }
  
    static Future<ClosureConversionContext> create(
        Chain suite, Map<String, String> environment) async {
      Uri sdk = await computePatchedSdk();
      Uri packages = Uri.base.resolve(".packages");
      bool strongMode = environment.containsKey(STRONG_MODE);
      bool updateExpectations = environment["updateExpectations"] == "true";
      UriTranslator uriTranslator = await UriTranslatorImpl
          .parse(PhysicalFileSystem.instance, sdk, packages: packages);
      return new ClosureConversionContext(
          strongMode, updateExpectations, uriTranslator);
    }
  }
  
  
negative.code: 
  import 'dart:async' show Future;
  
  import 'package:kernel/core_types.dart' show CoreTypes;
  
  import 'package:testing/testing.dart'
      show Chain, ChainContext, Result, Step, runMe;
  
  import 'package:kernel/ast.dart' show Program, Library;
  
  