### Question:
TemplateLayout extends FrameLayout { @SuppressWarnings("unchecked") public <M extends Mixin> M getMixin(Class<M> cls) { return (M) mMixins.get(cls); } TemplateLayout(Context context, int template, int containerId);  TemplateLayout(Context context, AttributeSet attrs); @TargetApi(VERSION_CODES.HONEYCOMB)  TemplateLayout(Context context, AttributeSet attrs, int defStyleAttr); @SuppressWarnings("TypeParameterUnusedInFormals") T findManagedViewById(int id); @SuppressWarnings("unchecked") M getMixin(Class<M> cls); @Override void addView(View child, int index, ViewGroup.LayoutParams params); @Keep @TargetApi(VERSION_CODES.HONEYCOMB) void setXFraction(float fraction); @Keep @TargetApi(VERSION_CODES.HONEYCOMB) float getXFraction();  }### Answer:
@Test public void testGetMixin() { TemplateLayout layout = new TemplateLayout(mContext, R.layout.test_template, R.id.suw_layout_content); final HeaderMixin mixin = layout.getMixin(HeaderMixin.class); assertNull("getMixin for a mixin that doesn't exist should return null", mixin); }