Assert pictures in Robotium.

[hubert.tr...@gmail.com]

Hello all!
I am new to Robotium and i have a simple app:
1 ImageView
3 RadioButtons to change image in ImageView

I need to test that after click on radioButton, image changes to proper one:

public void testChangeColor() throws Exception{
 RadioButton radioButton = (RadioButton)solo.getView(R.id.radioButton);
 ImageView imageView = (ImageView)solo.getView(R.id.imageView);
 Drawable drawable = ContextCompat.getDrawable(imageView.getContext(),R.mipmap.android_image);

 solo.scrollToSide(Solo.RIGHT);
 solo.waitForFragmentById(R.layout.fragment_main);
 solo.clickOnView(radioButton);
 Thread.sleep(1000);
 Assert.assertEquals(imageView.getDrawable(), drawable);

}

Unfortunately this piece of code doesn't work. Any solutions? This should be very basic test though, but i couldn't find any tutorial or piece of knowledge.