Awesome
pytest-grpc
Write test for gRPC with pytest.
Example
See example dir and/or read 'usage'.
Usage
For example you have some proto file with rpc declaration.
syntax = "proto3";
package test.v1;
service EchoService {
rpc handler(EchoRequest) returns (EchoResponse) {
}
}
message EchoRequest {
string name = 1;
}
message EchoResponse {
string name = 1;
}
After compile it with grpcio-tools, you get *_pb2.py and *_pb2_grpc.py files, now you can write your service.
from stub.test_pb2 import EchoRequest, EchoResponse
from stub.test_pb2_grpc import EchoServiceServicer
class Servicer(EchoServiceServicer):
def handler(self, request: EchoRequest, context) -> EchoResponse:
return EchoResponse(name=f'test-{request.name}')
def error_handler(self, request: EchoRequest, context) -> EchoResponse:
raise RuntimeError('Some error')
Point pytest with your stubs and service:
import pytest
from stub.test_pb2 import EchoRequest
@pytest.fixture(scope='module')
def grpc_add_to_server():
from stub.test_pb2_grpc import add_EchoServiceServicer_to_server
return add_EchoServiceServicer_to_server
@pytest.fixture(scope='module')
def grpc_servicer():
from servicer import Servicer
return Servicer()
@pytest.fixture(scope='module')
def grpc_stub_cls(grpc_channel):
from stub.test_pb2_grpc import EchoServiceStub
return EchoServiceStub
Write little test:
def test_some(grpc_stub):
request = EchoRequest()
response = grpc_stub.handler(request)
assert response.name == f'test-{request.name}'
def test_example(grpc_stub):
request = EchoRequest()
response = grpc_stub.error_handler(request)
assert response.name == f'test-{request.name}'
Testing secure server
from pathlib import Path
import pytest
import grpc
@pytest.fixture(scope='module')
def grpc_add_to_server():
from stub.test_pb2_grpc import add_EchoServiceServicer_to_server
return add_EchoServiceServicer_to_server
@pytest.fixture(scope='module')
def grpc_servicer():
from servicer import Servicer
return Servicer()
@pytest.fixture(scope='module')
def grpc_stub_cls(grpc_channel):
from stub.test_pb2_grpc import EchoServiceStub
return EchoServiceStub
@pytest.fixture(scope='session')
def my_ssl_key_path():
return Path('/path/to/key.pem')
@pytest.fixture(scope='session')
def my_ssl_cert_path():
return Path('/path/to/cert.pem')
@pytest.fixture(scope='module')
def grpc_server(_grpc_server, grpc_addr, my_ssl_key_path, my_ssl_cert_path):
"""
Overwrites default `grpc_server` fixture with ssl credentials
"""
credentials = grpc.ssl_server_credentials([
(my_ssl_key_path.read_bytes(),
my_ssl_cert_path.read_bytes())
])
_grpc_server.add_secure_port(grpc_addr, server_credentials=credentials)
_grpc_server.start()
yield _grpc_server
_grpc_server.stop(grace=None)
@pytest.fixture(scope='module')
def my_channel_ssl_credentials(my_ssl_cert_path):
# If we're using self-signed certificate it's necessarily to pass root certificate to channel
return grpc.ssl_channel_credentials(
root_certificates=my_ssl_cert_path.read_bytes()
)
@pytest.fixture(scope='module')
def grpc_channel(my_channel_ssl_credentials, create_channel):
"""
Overwrites default `grpc_channel` fixture with ssl credentials
"""
with create_channel(my_channel_ssl_credentials) as channel:
yield channel
@pytest.fixture(scope='module')
def grpc_authorized_channel(my_channel_ssl_credentials, create_channel):
"""
Channel with authorization header passed
"""
grpc_channel_credentials = grpc.access_token_call_credentials("some_token")
composite_credentials = grpc.composite_channel_credentials(
my_channel_ssl_credentials,
grpc_channel_credentials
)
with create_channel(composite_credentials) as channel:
yield channel
@pytest.fixture(scope='module')
def my_authorized_stub(grpc_stub_cls, grpc_channel):
"""
Stub with authorized channel
"""
return grpc_stub_cls(grpc_channel)
Run tests against real gRPC server
Run tests against read grpc server worked in another thread:
py.test
cachedir: .pytest_cache
plugins: grpc-0.0.0
collected 2 items
example/test_example.py::test_some PASSED
example/test_example.py::test_example FAILED
=================================== FAILURES ====================================
_________________________________ test_example __________________________________
grpc_stub = <stub.test_pb2_grpc.EchoServiceStub object at 0x107a9b390>
def test_example(grpc_stub):
request = EchoRequest()
> response = grpc_stub.error_handler(request)
example/test_example.py:35:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
.env/lib/python3.7/site-packages/grpc/_channel.py:547: in __call__
return _end_unary_response_blocking(state, call, False, None)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
state = <grpc._channel._RPCState object at 0x107b263c8>
call = <grpc._cython.cygrpc.SegregatedCall object at 0x107b323c8>
with_call = False, deadline = None
def _end_unary_response_blocking(state, call, with_call, deadline):
if state.code is grpc.StatusCode.OK:
if with_call:
rendezvous = _Rendezvous(state, call, None, deadline)
return state.response, rendezvous
else:
return state.response
else:
> raise _Rendezvous(state, None, None, deadline)
E grpc._channel._Rendezvous: <_Rendezvous of RPC that terminated with:
E status = StatusCode.UNKNOWN
E details = "Exception calling application: Some error"
E debug_error_string = "{"created":"@1544451353.148337000","description":"Error received from peer","file":"src/core/lib/surface/call.cc","file_line":1036,"grpc_message":"Exception calling application: Some error","grpc_status":2}"
E >
.env/lib/python3.7/site-packages/grpc/_channel.py:466: _Rendezvous
------------------------------- Captured log call -------------------------------
_server.py 397 ERROR Exception calling application: Some error
Traceback (most recent call last):
File "pytest-grpc/.env/lib/python3.7/site-packages/grpc/_server.py", line 389, in _call_behavior
return behavior(argument, context), True
File "pytest-grpc/example/src/servicer.py", line 10, in error_handler
raise RuntimeError('Some error')
RuntimeError: Some error
================ 1 failed, 1 passed, 1 warnings in 0.16 seconds =================
Run tests directly to python code
Call handlers directly, with fake grpc internals:
py.test --grpc-fake-server
In this case your get nice direct exceptions:
============================= test session starts =============================
cachedir: .pytest_cache
plugins: grpc-0.0.0
collected 2 items
example/test_example.py::test_some PASSED
example/test_example.py::test_example FAILED
================================== FAILURES ===================================
________________________________ test_example _________________________________
grpc_stub = <stub.test_pb2_grpc.EchoServiceStub object at 0x10e06f518>
def test_example(grpc_stub):
request = EchoRequest()
> response = grpc_stub.error_handler(request)
example/test_example.py:35:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
pytest_grpc/plugin.py:42: in fake_handler
return real_method(request, context)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
self = <servicer.Servicer object at 0x10ce75278>, request =
context = <pytest_grpc.plugin.FakeContext object at 0x10e083e48>
def error_handler(self, request: EchoRequest, context) -> EchoResponse:
> raise RuntimeError('Some error')
E RuntimeError: Some error
example/src/servicer.py:10: RuntimeError
=============== 1 failed, 1 passed, 1 warnings in 0.10 seconds ================
Run the servicer on multiple threads
The number of workers threads for gRPC can be specified in two ways:
- add
--grpc-max-workers=<n>to the arguments - test modules can also use a
grpc_max_workers=<n>variable
See test_blocking in example.