### Question:
ButtonFooterMixin implements Mixin { public void removeButton(Button button) { if (buttonContainer != null) { buttonContainer.removeView(button); } } ButtonFooterMixin(TemplateLayout layout); Button addButton(CharSequence text, @StyleRes int theme); Button addButton(@StringRes int text, @StyleRes int theme); Button addButton(Button button); View addSpace(); void removeButton(Button button); void removeSpace(View space); void removeAllViews();  }### Answer:
@Test public void testRemoveButton() { ButtonFooterMixin mixin = new ButtonFooterMixin(mTemplateLayout); final Button fooButton = mixin.addButton("foo", R.style.SuwGlifButton_Secondary); final Button barButton = mixin.addButton("bar", R.style.SuwGlifButton_Secondary); fooButton.setTag("foo"); barButton.setTag("bar"); assertNotNull("Foo button should exist", mStubParent.findViewWithTag("foo")); assertNotNull("Bar button should exist", mStubParent.findViewWithTag("bar")); mixin.removeButton(fooButton); assertNull("Foo button should be removed", mStubParent.findViewWithTag("foo")); assertNotNull("Bar button should not be removed", mStubParent.findViewWithTag("bar")); }