Updated tests

tests/test_image_converter.py

@@ -1,7 +1,15 @@
 """ test ImageConverter """
 
+import os
+
 import pytest
 
+skip_test = "OSXPHOTOS_TEST_CONVERT" not in os.environ
+pytestmark = pytest.mark.skipif(
+    skip_test, reason="Skip if running on GitHub actions, no GPU."
+)
+
+
 TEST_HEIC = "tests/test-images/IMG_3092.heic"
 TEST_RAW = "tests/test-images/IMG_0476_2.CR2"
 TEST_JPEG = "tests/test-images/IMG_3984.jpeg"