feat: add test for dependabot extra configuration at env level

README.md

@@ -160,7 +160,7 @@ maven:
   password: "${{secrets.password}}"
 ```
 
-The principal key of each configuration need to match the package managers that the [script is looking for](https://github.com/github/evergreen/blob/main/dependabot_file.py#L78).
+The principal key of each configuration need to match the package managers that the [script is looking for](https://docs.github.com/en/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file#package-ecosystem).
 
 The `dependabot.yaml` created file will look like the following with the `registries:` key added:
 

env.py

@@ -344,6 +344,10 @@ def get_env_vars(
         labels_list = [label.lower().strip() for label in labels_str.split(",")]
 
     dependabot_config_file = os.getenv("DEPENDABOT_CONFIG_FILE")
+    if dependabot_config_file and not os.path.exists(dependabot_config_file):
+        raise ValueError(
+            f"No dependabot extra configuration found. Please create one in {dependabot_config_file}"
+        )
 
     return (
         organization,

test_env.py

@@ -1301,6 +1301,26 @@ def test_get_env_vars_project_id_not_a_number(self):
             "PROJECT_ID environment variable is not numeric",
         )
 
+    @patch.dict(
+        os.environ,
+        {
+            "ORGANIZATION": "my_organization",
+            "GH_TOKEN": "my_token",
+            "SCHEDULE": "weekly",
+            "DEPENDABOT_CONFIG_FILE": "config.yaml",
+        },
+        clear=True,
+    )
+    def test_get_env_vars_with_dependabot_config_file_set_but_not_found(self):
+        """Test that no dependabot file configuration is present and the DEPENDABOT_CONFIG_FILE is set"""
+        with self.assertRaises(ValueError) as context_manager:
+            get_env_vars(True)
+        the_exception = context_manager.exception
+        self.assertEqual(
+            str(the_exception),
+            "No dependabot extra configuration found. Please create one in config.yaml",
+        )
+
 
 if __name__ == "__main__":
     unittest.main()