anchor.diff:              'b': [2],
             });
           });
  +        test('iterable converter (no providers)', () {
  +          final target = ['a', 'b', 'b'].toListMultimap();
  +          expect(target.keys, ['a', 'b']);
  +          expect(target.values, ['a', 'b', 'b']);
  +          expect(target.asMap(), {
  +            'a': ['a'],
  +            'b': ['b', 'b']
  +          });
  +        });
         });
         group('accessor', () {
           test('containsKey', () {
  
positive.code:           expect(target.asMap(), {
              'a': {1, 3},
              'b': {2},
            });
          });
        });
  
negative.code:         expect(target.keys, [1, 2, 3]);
          expect(target.values, ['a', 'b', 'c']);
        });
        test('iterable converter (default key and value providers)', () {
          final target = ['a', 'b'].toBiMap();
          expect(target.keys, ['a', 'b']);
          expect(target.values, ['a', 'b']);
        });
      });
      group('accessing', () {
        test('indexed', () {
  