### Question:
ProgressBarMixin implements Mixin { public ProgressBar peekProgressBar() { return (ProgressBar) templateLayout.findManagedViewById(R.id.suw_layout_progress); } ProgressBarMixin(TemplateLayout layout); boolean isShown(); void setShown(boolean shown); ProgressBar peekProgressBar(); void setColor(@Nullable ColorStateList color); @Nullable ColorStateList getColor();  }### Answer:
@Test public void testPeekProgressBar() { ProgressBarMixin mixin = new ProgressBarMixin(mTemplateLayout); assertNull( "PeekProgressBar should return null when stub not inflated yet", mixin.peekProgressBar()); mixin.setShown(true); assertNotNull( "PeekProgressBar should be available after setting to shown", mixin.peekProgressBar()); }