anchor.diff:      codecCompleter.complete(mockCodec);
       await tester.idle();
   
  -    final FrameInfo frame1 = FakeFrameInfo(20, 10, const Duration(milliseconds: 200));
  +    final FrameInfo frame1 = FakeFrameInfo(const Duration(milliseconds: 200), image20x10);
       mockCodec.completeNextFrame(frame1);
       await tester.idle();
       // We are waiting for the next animation tick, so at this point no frames
  
positive.code:     codecCompleter.complete(mockCodec);
      await tester.idle();
  
      final FrameInfo frame1 = FakeFrameInfo(20, 10, const Duration(milliseconds: 200));
      final FrameInfo frame2 = FakeFrameInfo(200, 100, const Duration(milliseconds: 400));
  
      mockCodec.completeNextFrame(frame1);
      await tester.idle(); // let nextFrameFuture complete
  
negative.code:     await tester.pump();
      expect(emittedImages, equals(<ImageInfo>[ImageInfo(image: frame1.image)]));
  
      final FrameInfo frame2 = FakeFrameInfo(const Duration(milliseconds: 400), image200x100);
      mockCodec.completeNextFrame(frame2);
  
      await tester.pump(const Duration(milliseconds: 100));
  