Added a test to check if datasets are not run because openml.org does not work

See https://github.com/orgs/openml/discussions/20

Author: martinlschumann

test_linear_ensemble.py

@@ -18,6 +18,7 @@ def test_output_str(self):
         """Tests, given a certain model, whether the expected output results occur"""
         # so that the maximum diff is printed
         self.maxDiff = None
+        counter = 0
         for fetched_dataset, openml_dataset, combined_df in get_custom_datasets(self.custom_datagroup_testing):
             try:
                 f = io.StringIO()
@@ -34,7 +35,8 @@ def test_output_str(self):
                     self.assertEqual(str(output_appender), f.getvalue())
             except Exception as e:
                 self.fail(f"Exception '{e}' occurred")
-
+            counter += 1
+        self.assertEqual(counter, len(self.custom_datagroup_testing), msg=f"Less datasets were run than expected: {counter} vs {len(self.custom_datagroup_testing)}")
 
 if __name__ == '__main__':
     unittest.main()