anchor.diff:          await tester.drag(find.text('1'), const Offset(0.0, 120.0));
           await tester.pump();
   
  -        verify(mockHelper.builder(
  -          any,
  -          RefreshIndicatorMode.drag,
  -          4.615384615384642,
  -          100.0, // Default value.
  -          60.0, // Default value.
  -        ));
  +        expect(mockHelper.invocations, contains(matchesBuilder(
  +          refreshState: RefreshIndicatorMode.done,
  +          pulledExtent: 4.615384615384642,
  +          refreshTriggerPullDistance: 100,  // default value.
  +          refreshIndicatorExtent: 60,  // default value.
  +        )));
   
           // Snaps away normally.
           await tester.pump();
  
positive.code:           child: CustomScrollView(
              slivers: <Widget>[
                CupertinoSliverRefreshControl(
                  builder: builder,
                ),
                buildAListOfStuff(),
              ],
  
negative.code:         // Start a refresh.
          await gesture.moveBy(const Offset(0.0, 150.0));
          await tester.pump();
          expect(mockHelper.invocations, contains(const RefreshTaskInvocation()));
  
          // Complete the task while held down.
          mockHelper.refreshCompleter.complete(null);
          await tester.pump();
  
          expect(mockHelper.invocations, contains(matchesBuilder(
            refreshState: RefreshIndicatorMode.done,
            pulledExtent: 150.0, // Still overscrolled here.
            refreshTriggerPullDistance: 100,  // default value.
            refreshIndicatorExtent: 60,  // default value.
          )));
          expect(
            tester.getRect(find.widgetWithText(Center, '0')),
            const Rect.fromLTRB(0.0, 150.0, 800.0, 350.0),
  