def METHOD_NAME(self):
    # Get MNIST
    (x, _), (_, _), _, _ = load_mnist(raw=True)
    n = 100
    x = x[:n]
    # Test RGB
    x_rgb = convert_to_rgb(x)
    s_original = np.shape(x)
    s_new = np.shape(x_rgb)
    self.assertEqual(s_new[0], s_original[0])
    self.assertEqual(s_new[1], s_original[1])
    self.assertEqual(s_new[2], s_original[2])
    self.assertEqual(s_new[3], 3)  # Should have added 3 channels