tests: add testing w/o 'grpc' installed (#289)

Closes #288.

Author: tseaver

noxfile.py

@@ -33,6 +33,7 @@
 nox.options.sessions = [
     "unit",
     "unit_grpc_gcp",
+    "unit_wo_grpc",
     "cover",
     "pytype",
     "mypy",
@@ -78,7 +79,7 @@ def blacken(session):
     session.run("black", *BLACK_EXCLUDES, *BLACK_PATHS)
 
 
-def default(session):
+def default(session, install_grpc=True):
     """Default unit test session.
 
     This is intended to be run **without** an interpreter set, so
@@ -92,7 +93,10 @@ def default(session):
 
     # Install all test dependencies, then install this package in-place.
     session.install("mock", "pytest", "pytest-cov")
-    session.install("-e", ".[grpc]", "-c", constraints_path)
+    if install_grpc:
+        session.install("-e", ".[grpc]", "-c", constraints_path)
+    else:
+        session.install("-e", ".", "-c", constraints_path)
 
     pytest_args = [
         "python",
@@ -140,6 +144,12 @@ def unit_grpc_gcp(session):
     default(session)
 
 
+@nox.session(python=["3.6", "3.10"])
+def unit_wo_grpc(session):
+    """Run the unit test suite w/o grpcio installed"""
+    default(session, install_grpc=False)
+
+
 @nox.session(python="3.6")
 def lint_setup_py(session):
     """Verify that setup.py is valid (including RST check)."""

tests/asyncio/gapic/test_config_async.py

@@ -12,6 +12,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+
+import pytest
+
+try:
+    import grpc  # noqa: F401
+except ImportError:
+    pytest.skip("No GRPC", allow_module_level=True)
+
 from google.api_core import exceptions
 from google.api_core.gapic_v1 import config_async
 

tests/asyncio/gapic/test_method_async.py

@@ -14,10 +14,14 @@
 
 import datetime
 
-from grpc import aio
 import mock
 import pytest
 
+try:
+    from grpc import aio
+except ImportError:
+    pytest.skip("No GRPC", allow_module_level=True)
+
 from google.api_core import exceptions
 from google.api_core import gapic_v1
 from google.api_core import grpc_helpers_async

tests/asyncio/operations_v1/test_operations_async_client.py

@@ -12,11 +12,17 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from grpc import aio
 import mock
 import pytest
 
-from google.api_core import grpc_helpers_async, operations_v1, page_iterator_async
+try:
+    from grpc import aio
+except ImportError:
+    pytest.skip("No GRPC", allow_module_level=True)
+
+from google.api_core import grpc_helpers_async
+from google.api_core import operations_v1
+from google.api_core import page_iterator_async
 from google.longrunning import operations_pb2
 from google.protobuf import empty_pb2
 

tests/asyncio/test_grpc_helpers_async.py

@@ -12,10 +12,19 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import grpc
-from grpc import aio
 import mock
-import pytest
+import pytest  # noqa: I202
+
+try:
+    import grpc
+    from grpc import aio
+except ImportError:
+    grpc = aio = None
+
+
+if grpc is None:
+    pytest.skip("No GRPC", allow_module_level=True)
+
 
 from google.api_core import exceptions
 from google.api_core import grpc_helpers_async

tests/asyncio/test_operation_async.py

@@ -16,6 +16,11 @@
 import mock
 import pytest
 
+try:
+    import grpc  # noqa: F401
+except ImportError:
+    pytest.skip("No GRPC", allow_module_level=True)
+
 from google.api_core import exceptions
 from google.api_core import operation_async
 from google.api_core import operations_v1

tests/unit/gapic/test_client_info.py

@@ -12,6 +12,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import pytest
+
+try:
+    import grpc  # noqa: F401
+except ImportError:
+    pytest.skip("No GRPC", allow_module_level=True)
+
 
 from google.api_core.gapic_v1 import client_info
 

tests/unit/gapic/test_config.py

@@ -12,6 +12,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import pytest
+
+try:
+    import grpc  # noqa: F401
+except ImportError:
+    pytest.skip("No GRPC", allow_module_level=True)
+
 from google.api_core import exceptions
 from google.api_core.gapic_v1 import config
 

tests/unit/gapic/test_method.py

@@ -15,6 +15,13 @@
 import datetime
 
 import mock
+import pytest
+
+try:
+    import grpc  # noqa: F401
+except ImportError:
+    pytest.skip("No GRPC", allow_module_level=True)
+
 
 from google.api_core import exceptions
 from google.api_core import retry

tests/unit/gapic/test_routing_header.py

@@ -12,6 +12,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import pytest
+
+try:
+    import grpc  # noqa: F401
+except ImportError:
+    pytest.skip("No GRPC", allow_module_level=True)
+
 
 from google.api_core.gapic_v1 import routing_header