Bitmap.CreateBitmap return null in JUnit Testing Android Studio

I need to create a fake bitmap image for testing (JUnit Test) my personal add and get methods of a custom LinkedList but the Bitmap.createBitmap return the error:

java.lang.RuntimeException: Method createBitmap in android.graphics.Bitmap not mocked.

This is the code of my JUnitTest:

public class TicketsIteratorTest {

    Bitmap img_Bmp;
    TicketsIterator<Bitmap> TicketsList = new TicketsIterator();

    /*
     * Test for the add e get methods, check if the element just insert it's the same of the one just extract.
     */
    @Test
    public void Add_n_Get() throws Exception {
        int i = 0, numIMG = 100;
        Bitmap[] IMG_Generated;
        IMG_Generated = new Bitmap[numIMG];

        // Generate numIMG of imagine to insert into the Iterator and it save each one of it into an
        // Bitmap array usefull for testing of the get method
        while (i <= numIMG) {
            // Generation of the fake Ticket Bitmap
            try {
                img_Bmp = Bitmap.createBitmap(100, 100, Bitmap.Config.ARGB_8888);

                IMG_Generated[i] = img_Bmp;

            } catch (Exception e) {
                // Print the cause of the error just generated
                e.getCause().printStackTrace();
            }

            // Addition of the imagine just created
            TicketsList.add(img_Bmp);

            i++;
        }

        // Test if the imagine inserted it is correct
        while (i <= numIMG) {
            assertTrue(IMG_Generated[i] == TicketsList.get(IMG_Generated[i]));
            i++;
        }
    }

Thank you for the help.