Refactor 'client_info' support. (#7849)

* Add 'user_agent' and 'extra_headers' properties to 'Connection'.

   Deprecate the 'USER_AGENT' and '_EXTRA_HEADERS' class-level attributes.

* Add 'client_info' parameter to 'Connection' ctor.

* Implement 'Connection.user_agent' via its '_client_info'.

* Ensure 'X-Goog-API-Client' header is always passed.

* Create/use non-GAPIC-specific 'ClientInfo' class FBO HTTP/JSON clients.

  Derive the existing GAPIC class from it.

2 files changed, 69 insertions, 53 deletions

diff --git a/tests/unit/gapic/test_client_info.py b/tests/unit/gapic/test_client_info.py
index 0cca479..64080ff 100644
--- a/tests/unit/gapic/test_client_info.py
+++ b/tests/unit/gapic/test_client_info.py
@@ -16,59 +16,6 @@
 from google.api_core.gapic_v1 import client_info
 
 
-def test_constructor_defaults():
-    info = client_info.ClientInfo()
-
-    assert info.python_version is not None
-    assert info.grpc_version is not None
-    assert info.api_core_version is not None
-    assert info.gapic_version is None
-    assert info.client_library_version is None
-
-
-def test_constructor_options():
-    info = client_info.ClientInfo(
-        python_version="1",
-        grpc_version="2",
-        api_core_version="3",
-        gapic_version="4",
-        client_library_version="5",
-        user_agent="6"
-    )
-
-    assert info.python_version == "1"
-    assert info.grpc_version == "2"
-    assert info.api_core_version == "3"
-    assert info.gapic_version == "4"
-    assert info.client_library_version == "5"
-    assert info.user_agent == "6"
-
-
-def test_to_user_agent_minimal():
-    info = client_info.ClientInfo(
-        python_version="1", api_core_version="2", grpc_version=None
-    )
-
-    user_agent = info.to_user_agent()
-
-    assert user_agent == "gl-python/1 gax/2"
-
-
-def test_to_user_agent_full():
-    info = client_info.ClientInfo(
-        python_version="1",
-        grpc_version="2",
-        api_core_version="3",
-        gapic_version="4",
-        client_library_version="5",
-        user_agent="app-name/1.0",
-    )
-
-    user_agent = info.to_user_agent()
-
-    assert user_agent == "app-name/1.0 gl-python/1 grpc/2 gax/3 gapic/4 gccl/5"
-
-
 def test_to_grpc_metadata():
     info = client_info.ClientInfo()
 
diff --git a/tests/unit/test_client_info.py b/tests/unit/test_client_info.py
new file mode 100644
index 0000000..0eb17c5
--- /dev/null
+++ b/tests/unit/test_client_info.py
@@ -0,0 +1,69 @@
+# Copyright 2017 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+from google.api_core import client_info
+
+
+def test_constructor_defaults():
+    info = client_info.ClientInfo()
+
+    assert info.python_version is not None
+    assert info.grpc_version is not None
+    assert info.api_core_version is not None
+    assert info.gapic_version is None
+    assert info.client_library_version is None
+
+
+def test_constructor_options():
+    info = client_info.ClientInfo(
+        python_version="1",
+        grpc_version="2",
+        api_core_version="3",
+        gapic_version="4",
+        client_library_version="5",
+        user_agent="6"
+    )
+
+    assert info.python_version == "1"
+    assert info.grpc_version == "2"
+    assert info.api_core_version == "3"
+    assert info.gapic_version == "4"
+    assert info.client_library_version == "5"
+    assert info.user_agent == "6"
+
+
+def test_to_user_agent_minimal():
+    info = client_info.ClientInfo(
+        python_version="1", api_core_version="2", grpc_version=None
+    )
+
+    user_agent = info.to_user_agent()
+
+    assert user_agent == "gl-python/1 gax/2"
+
+
+def test_to_user_agent_full():
+    info = client_info.ClientInfo(
+        python_version="1",
+        grpc_version="2",
+        api_core_version="3",
+        gapic_version="4",
+        client_library_version="5",
+        user_agent="app-name/1.0",
+    )
+
+    user_agent = info.to_user_agent()
+
+    assert user_agent == "app-name/1.0 gl-python/1 grpc/2 gax/3 gapic/4 gccl/5"