Fix #44: Raise explicit error when API Key is missing

tests/test_tiingo.py

@@ -25,6 +25,17 @@ def test_client_repr():
     assert repr(client) == "<TiingoClient(url=\"{}\")>".format(base_url)
 
 
+class TestClient(TestCase):
+
+    def test_api_key_missing_error(self):
+        config = {
+            'api_key': ""
+        }
+        with self.assertRaises(RuntimeError):
+            client = TiingoClient(config=config)
+            assert client
+
+
 # PRICES ENDPOINTS
 class TestTickerPrices(TestCase):
 

tiingo/api.py

@@ -60,7 +60,10 @@ class TiingoClient(RestClient):
             api_key = self._config['api_key']
         except KeyError:
             api_key = os.environ.get('TIINGO_API_KEY')
-        assert(api_key)
+
+        if not(api_key):
+            raise RuntimeError("Tiingo API Key not provided. Please provide"
+                               " via environment variable or config argument.")
 
         self._headers = {
             'Authorization': "Token {}".format(api_key),