Bigtable: deprecate 'channel' arg to 'Client' (#6279)

We can't do anything with it, because it conflicts with the credentials
we (always) have.

Also, add explicit tests for 'Client' constructor, including assertions
for all attributes.

bigtable/google/cloud/bigtable/client.py

@@ -27,7 +27,7 @@
 * a :class:`~google.cloud.bigtable.table.Table` owns a
   :class:`~google.cloud.bigtable.row.Row` (and all the cells in the row)
 """
-
+import warnings
 
 from google.api_core.gapic_v1 import client_info
 
@@ -87,10 +87,10 @@ class Client(ClientWithProject):
                   requires the :const:`ADMIN_SCOPE`. Defaults to :data:`False`.
 
     :type channel: :instance: grpc.Channel
-    :param channel (grpc.Channel): (Optional) A ``Channel`` instance
-            through which to make calls. This argument is mutually
-            exclusive with ``credentials``; providing both will raise an
-            exception.
+    :param channel (grpc.Channel): (Optional) DEPRECATED:
+            A ``Channel`` instance through which to make calls.
+            This argument is mutually exclusive with ``credentials``;
+            providing both will raise an exception. No longer used.
 
     :raises: :class:`ValueError <exceptions.ValueError>` if both ``read_only``
              and ``admin`` are :data:`True`
@@ -109,6 +109,12 @@ def __init__(self, project=None, credentials=None,
         #       It **may** use those scopes in ``with_scopes_if_required``.
         self._read_only = bool(read_only)
         self._admin = bool(admin)
+
+        if channel is not None:
+            warnings.warn(
+                "'channel' is deprecated and no longer used.",
+                DeprecationWarning, stacklevel=2)
+
         self._channel = channel
         self.SCOPE = self._get_scopes()
         super(Client, self).__init__(project=project, credentials=credentials)
@@ -145,8 +151,7 @@ def project_path(self):
         :rtype: str
         :returns: Return a fully-qualified project string.
         """
-        instance_client = self.instance_admin_client
-        return instance_client.project_path(self.project)
+        return self.instance_admin_client.project_path(self.project)
 
     @property
     def table_data_client(self):

bigtable/tests/unit/test_client.py

@@ -36,6 +36,49 @@ def _get_target_class():
     def _make_one(self, *args, **kwargs):
         return self._get_target_class()(*args, **kwargs)
 
+    def test_constructor_defaults(self):
+        from google.cloud.bigtable.client import DATA_SCOPE
+
+        credentials = _make_credentials()
+
+        with mock.patch('google.auth.default') as mocked:
+            mocked.return_value = credentials, self.PROJECT
+            client = self._make_one()
+
+        self.assertEqual(client.project, self.PROJECT)
+        self.assertIs(
+            client._credentials, credentials.with_scopes.return_value)
+        self.assertFalse(client._read_only)
+        self.assertFalse(client._admin)
+        self.assertIsNone(client._channel)
+        self.assertEqual(client.SCOPE, (DATA_SCOPE,))
+
+    def test_constructor_explicit(self):
+        import warnings
+        from google.cloud.bigtable.client import ADMIN_SCOPE
+        from google.cloud.bigtable.client import DATA_SCOPE
+
+        credentials = _make_credentials()
+
+        with warnings.catch_warnings(record=True) as warned:
+            client = self._make_one(
+                project=self.PROJECT,
+                credentials=credentials,
+                read_only=False,
+                admin=True,
+                channel=mock.sentinel.channel,
+            )
+
+        self.assertEqual(len(warned), 1)
+
+        self.assertEqual(client.project, self.PROJECT)
+        self.assertIs(
+            client._credentials, credentials.with_scopes.return_value)
+        self.assertFalse(client._read_only)
+        self.assertTrue(client._admin)
+        self.assertIs(client._channel, mock.sentinel.channel)
+        self.assertEqual(client.SCOPE, (DATA_SCOPE, ADMIN_SCOPE))
+
     def test_constructor_both_admin_and_read_only(self):
         credentials = _make_credentials()
         with self.assertRaises(ValueError):
@@ -68,63 +111,14 @@ def test__get_scopes_read_only(self):
             read_only=True)
         self.assertEqual(client._get_scopes(), (READ_ONLY_SCOPE,))
 
-    def test_credentials_getter(self):
-        credentials = _make_credentials()
-        project = 'PROJECT'
-        client = self._make_one(
-            project=project, credentials=credentials)
-        self.assertIs(client._credentials,
-                      credentials.with_scopes.return_value)
-
-    def test_project_name_property(self):
+    def test_project_path_property(self):
         credentials = _make_credentials()
         project = 'PROJECT'
         client = self._make_one(project=project, credentials=credentials,
                                 admin=True)
         project_name = 'projects/' + project
         self.assertEqual(client.project_path, project_name)
 
-    def test_instance_factory_defaults(self):
-        from google.cloud.bigtable.instance import Instance
-
-        PROJECT = 'PROJECT'
-        INSTANCE_ID = 'instance-id'
-        credentials = _make_credentials()
-        client = self._make_one(
-            project=PROJECT, credentials=credentials)
-
-        instance = client.instance(INSTANCE_ID)
-
-        self.assertIsInstance(instance, Instance)
-        self.assertEqual(instance.instance_id, INSTANCE_ID)
-        self.assertEqual(instance.display_name, INSTANCE_ID)
-        self.assertIsNone(instance.type_)
-        self.assertIsNone(instance.labels)
-        self.assertIs(instance._client, client)
-
-    def test_instance_factory_non_defaults(self):
-        from google.cloud.bigtable.instance import Instance
-        from google.cloud.bigtable import enums
-
-        PROJECT = 'PROJECT'
-        INSTANCE_ID = 'instance-id'
-        DISPLAY_NAME = 'display-name'
-        instance_type = enums.Instance.Type.DEVELOPMENT
-        labels = {'foo': 'bar'}
-        credentials = _make_credentials()
-        client = self._make_one(
-            project=PROJECT, credentials=credentials)
-
-        instance = client.instance(INSTANCE_ID, display_name=DISPLAY_NAME,
-                                   instance_type=instance_type, labels=labels)
-
-        self.assertIsInstance(instance, Instance)
-        self.assertEqual(instance.instance_id, INSTANCE_ID)
-        self.assertEqual(instance.display_name, DISPLAY_NAME)
-        self.assertEqual(instance.type_, instance_type)
-        self.assertEqual(instance.labels, labels)
-        self.assertIs(instance._client, client)
-
     def test_table_data_client_not_initialized(self):
         from google.cloud.bigtable_v2 import BigtableClient
 
@@ -194,6 +188,47 @@ def test_instance_admin_client_initialized(self):
         already = client._instance_admin_client = object()
         self.assertIs(client.instance_admin_client, already)
 
+    def test_instance_factory_defaults(self):
+        from google.cloud.bigtable.instance import Instance
+
+        PROJECT = 'PROJECT'
+        INSTANCE_ID = 'instance-id'
+        credentials = _make_credentials()
+        client = self._make_one(
+            project=PROJECT, credentials=credentials)
+
+        instance = client.instance(INSTANCE_ID)
+
+        self.assertIsInstance(instance, Instance)
+        self.assertEqual(instance.instance_id, INSTANCE_ID)
+        self.assertEqual(instance.display_name, INSTANCE_ID)
+        self.assertIsNone(instance.type_)
+        self.assertIsNone(instance.labels)
+        self.assertIs(instance._client, client)
+
+    def test_instance_factory_non_defaults(self):
+        from google.cloud.bigtable.instance import Instance
+        from google.cloud.bigtable import enums
+
+        PROJECT = 'PROJECT'
+        INSTANCE_ID = 'instance-id'
+        DISPLAY_NAME = 'display-name'
+        instance_type = enums.Instance.Type.DEVELOPMENT
+        labels = {'foo': 'bar'}
+        credentials = _make_credentials()
+        client = self._make_one(
+            project=PROJECT, credentials=credentials)
+
+        instance = client.instance(INSTANCE_ID, display_name=DISPLAY_NAME,
+                                   instance_type=instance_type, labels=labels)
+
+        self.assertIsInstance(instance, Instance)
+        self.assertEqual(instance.instance_id, INSTANCE_ID)
+        self.assertEqual(instance.display_name, DISPLAY_NAME)
+        self.assertEqual(instance.type_, instance_type)
+        self.assertEqual(instance.labels, labels)
+        self.assertIs(instance._client, client)
+
     def test_list_instances(self):
         from google.cloud.bigtable_admin_v2.proto import (
             instance_pb2 as data_v2_pb2)