How do I add to the MediaStore for testing with Robolectric

My goal is to test some Android App code that gets a list of image files that are on the device and then does some work on that list.

I am new to Android and Android Unit testing.

I am attempting to add images to the MediaStore within a Robolectric unit test, but I am not sure how to proceed.

These are the steps I think I need to perform:

1. Add the Test Images to a known directory on the local system.
2. Copy the images to the Robolectric Temp directory that the Media Service will expect or can be pointed to.

3. Then run insertImage and add the images to the MediaStore.

   MediaStore.Images.Media.insertImage(...);

When I attempt to insert the image however the method returns null.

I have images, but I am not sure where to copy them for the MediaStore to understand, and I am not sure why when I run the insertImage on a known image path I get a null return. I am not longer getting a FileNotFound exception so I believe it is finding the file.