YAML Formatting & Validation (#347)

* leverage yamllint in GitHub actions 

* add pre-commits

* validation updates

* Update README.md

* Update CONTRIBUTING.md

tests/definitions_test.py

@@ -0,0 +1,54 @@
+import glob
+import json
+import pytest
+import yaml
+from jsonschema import validate
+from jsonschema.exceptions import ValidationError
+
+
+def _get_definition_files():
+    """
+    Return a list of all definition files.
+    """
+    return [f for f in glob.glob("device-types/*/*", recursive=True)]
+
+
+# Initialize schema
+with open("tests/schema.json") as schema_file:
+    schema = json.loads(schema_file.read())
+
+
+def test_environment():
+    """
+    Run basic sanity checks on the environment to ensure tests are running correctly.
+    """
+    # Validate that definition files exist
+    assert _get_definition_files(), "No definition files found!"
+
+    # Validate that the schema exists
+    assert schema, "Schema definition is empty!"
+
+
+@pytest.mark.parametrize("file_path", _get_definition_files())
+def test_definition(file_path):
+    """
+    Validate each DeviceType definition file using the provided JSON schema.
+    """
+    # Check file extension
+    assert file_path.split('.')[-1] in ('yaml', 'yml'), f"Invalid file extension: {file_path}"
+
+    # Read file
+    with open(file_path) as definition_file:
+        content = definition_file.read()
+
+        # Check for trailing newline
+        assert content[-1] == '\n', "Missing trailing newline"
+
+        # Load YAML data
+        definition = yaml.load(content, Loader=yaml.SafeLoader)
+
+    # Run validation
+    try:
+        validate(definition, schema=schema)
+    except ValidationError as e:
+        pytest.fail(f"{file_path} failed validation: {e}", False)