Back out ClientBase subclassing.

firestore/google/cloud/firestore/client.py

@@ -14,18 +14,13 @@
 
 """Firestore database API."""
 
-from google.cloud.client import Client as _BaseClient
-from google.cloud.client import _ClientProjectMixin
 
-
-class Client(_BaseClient, _ClientProjectMixin):
+class Client(object):
     """Top level Firestore database instance.
 
-    :type project_id: str
-    :param project_id: (optional) Project containing the Firestore database.
+    :type project: str
+    :param project: (optional) Project containing the Firestore database.
     """
 
-    def __init__(self, project_id=None):
-        _ClientProjectMixin.__init__(self, project=project_id)
-        super(Client, self).__init__()
-        self.database_id = None
+    def __init__(self, project=None):
+        raise NotImplementedError()

firestore/unit_tests/test_client.py

@@ -15,18 +15,12 @@
 
 import unittest
 
-from six import string_types
-
 from google.cloud.firestore import Client
 
 
 class TestFirestore(unittest.TestCase):
-    """Unit Tests for the google.cloud.firestore.Firestore."""
-
-    def test_empty_constructor(self):
-        db = Client()
-        self.assertIsInstance(db.project, string_types)
+    """Unit Tests for the google.cloud.firestore.Client."""
 
     def test_constructor(self):
-        db = Client('my-project-id')
-        self.assertEqual(db.project, 'my-project-id')
+        with self.assertRaises(NotImplementedError):
+            Client('my-project-id')