Test: add test for env vars in yaml

tests/test_yaml_files.py

@@ -21,6 +21,16 @@ class TestYaml(unittest.TestCase):
         except KeyError as ke:
             self.fail(f"Could not create Config from dict: {yaml_dict}.\n{ke}")
 
+    def test_read_docker_yaml_config(self):
+        """Reads the docker yaml file."""
+        docker_path = os.path.join(self.tests_root_dir, "config/for-docker.yaml")
+        yaml_dict = self.recorder.read_yaml_config(docker_path)
+        self.assertIsInstance(yaml_dict, dict)
+        try:
+            recorder.Config(yaml_dict)
+        except KeyError as ke:
+            self.fail(f"Could not create Config from dict: {yaml_dict}.\n{ke}")
+
     def test_read_faulty_yaml_config(self):
         """Reads faulty yaml files in engine-recorder/tests/config/."""
         faulty_dir = os.path.join(self.tests_root_dir, "tests/config")