Add test that checks whether API test is complete

Author: mwcraig

tests/test_astro_image_display_api.py

@@ -0,0 +1,30 @@
+from astropy.utils.data import get_pkg_data_contents
+
+from astro_image_display_api.interface_definition import ImageViewerInterface
+from astro_image_display_api.dummy_viewer import ImageViewer
+from astro_image_display_api.widget_api_test import ImageWidgetAPITest
+
+def test_api_test_class_completeness():
+    """
+    Test that the ImageWidgetAPITest class is complete and has tests
+    for all of the required methods and attributes.
+    """
+    # Get the attributes on the protocol
+    required_attributes = ImageViewerInterface.__protocol_attrs__
+
+    # Get the text of the api tests
+    widget_api_test_content = get_pkg_data_contents("widget_api_test.py", package="astro_image_display_api")
+    # Loop over the attributes and check that the test class has a method
+    # for each one whose name starts with test_ and ends with the attribute
+    # name.
+    attr_present = []
+    image_viewer_name = "self.image"
+    for attr in required_attributes:
+        attr_present.append(f"{image_viewer_name}.{attr}" in widget_api_test_content)
+
+
+
+    assert all(attr_present), (
+        "ImageWidgetAPITest is does not access these attributes/methods:\n "
+        f"{"\n".join(attr for attr, present in zip(required_attributes, attr_present) if not present)}. "
+    )