added tests and code for type validation during load (#2)

src/wagglemsg/__init__.py

@@ -34,9 +34,23 @@ def load(body: bytes) -> Message:
     """dump deserializes a Message object."""
     data = json.loads(body)
 
+    # use default empty dict
+    if "meta" not in data:
+        data["meta"] = {}
+
     if data.get("enc") == "b64":
         data["val"] = base64.b64decode(data["val"])
 
+    # check data types
+    if not isinstance(data["name"], str):
+        raise TypeError("name must have type str")
+
+    if not isinstance(data["ts"], int):
+        raise TypeError("ts must have type int")
+
+    if not isinstance(data["meta"], dict):
+        raise TypeError("meta must have type dict[str, str]")
+
     return Message(
         name=data["name"],
         value=data["val"],

tests/test_wagglemsg.py

@@ -4,6 +4,18 @@
 
 class TestMain(unittest.TestCase):
 
+    def test_meta_default(self):
+        msg = wagglemsg.load('{"name":"env.temperature","val":0,"ts":0}')
+        self.assertEqual(msg.meta, {})
+
+    def test_validate_types(self):
+        with self.assertRaises(TypeError):
+            wagglemsg.load('{"name":null,"val":0,"ts":0}')
+        with self.assertRaises(TypeError):
+            wagglemsg.load('{"name":"env.temperature","val":0,"ts":"123"}')
+        with self.assertRaises(TypeError):
+            wagglemsg.load('{"name":"env.temperature","val":0,"ts":0,"meta":null}')
+
     def test_fail(self):
         test_cases = [
             wagglemsg.Message(