anchor.diff:            fail('parse should fail');
           } on CheckedFromJsonException catch (e) {
             final prettyOutput = _prettyPrintCheckedFromJsonException(e);
  -          printOnFailure(prettyOutput);
  +          printOnFailure("r'''\n$prettyOutput'''");
             expect(prettyOutput, entry.value);
           }
         });
  
positive.code: Unrecognized keys: [baz, foo]; supported keys: [target, import, is_optional, configLocation, auto_apply, build_to, defaultEnumTest, builder_factories, applies_builders, required_inputs, build_extensions]
  
  line 4, column 5 of file.yaml: Invalid key "baz"
      baz: zap
      ^^^
  line 3, column 5 of file.yaml: Invalid key "foo"
      foo: bar
      ^^^''',
    r'''
    bob: cool
    ''': '''
  Could not create `Config`.
  line 1, column 3 of file.yaml: Required keys are missing: builders.
    bob: cool
    ^^^^^^^^^^''',
    r'''
  builders:
    builder_name:
      auto_apply:''': '''Could not create `Builder`.
  line 3, column 5 of file.yaml: These keys had `null` values, which is not allowed: [auto_apply]
      auto_apply:
      ^^^^^^^^^^^''',
    r'''
  builders:
    builder_name:
      builder_factories: ["scssBuilder"]
      configLocation: "user@host:invalid/uri"''':
        '''line 4, column 21 of file.yaml: Could not create `Builder`. Unsupported value for `configLocation`. Illegal scheme character at offset 4.
      configLocation: "user@host:invalid/uri"
                      ^^^^^^^^^^^^^^^^^^^^^^^'''
  };
  
  String _prettyPrintCheckedFromJsonException(CheckedFromJsonException err) {
  
negative.code:     auto_apply: unsupported
  ''': r'''
  line 4, column 17 of file.yaml: Could not create `Builder`. Unsupported value for `auto_apply`. `unsupported` is not one of the supported values: none, dependents, all_packages, root_package
    ╷
  4 │     auto_apply: unsupported
    │                 ^^^^^^^^^^^
    ╵''',
    r'''
  builders:
    a:
      builder_factories: []
    ''': r'''
  line 3, column 24 of file.yaml: Could not create `Builder`. Unsupported value for `builder_factories`. Must have at least one value.
    ╷
  3 │     builder_factories: []
    │                        ^^
    ╵''',
    r'''
  builders:
    a:
  