anchor.diff:    test("compiles a Sass file to CSS", () async {
       await d.file("test.scss", "a {b: 1 + 2}").create();
   
  -    var sass = await runSass(["test.scss", "test.css"]);
  +    var sass = await runSass(["test.scss"]);
       expect(
           sass.stdout,
           emitsInOrder([
  
positive.code:     test("with colors with --color", () async {
        await d.file("test.scss", "a {b: }").create();
  
        var sass = await runSass(["--color", "test.scss", "test.css"]);
        expect(
            sass.stderr,
            emitsInOrder([
  
negative.code:     test("for package urls", () async {
        await d.file("test.scss", "@import 'package:nope/test';").create();
  
        var sass = await runSass(["test.scss"]);
        expect(
            sass.stderr,
            emitsInOrder([
  