How to write a GRPC python unittest

Question

We are using grpc as the RPC protocol for all our internal system. Most of the system is written in Java.

In Java, we can use InprocessServerBuilder for unittest. However, I haven't find a similar class in Python.

Can any one provide a sample code for how to do GRPC unittest in python?

Answer 1

Some example code to get started:

proto

syntax = "proto3";

service MyLibrary {
    rpc Search (Request) returns (Response);
}

message Request {
    string id = 1;
}

message Response {
    string status = 1;
}

python unit test

#!/usr/bin/env python
# coding=utf-8

import unittest

from grpc import StatusCode
from grpc_testing import server_from_dictionary, strict_real_time
import mylibrary_pb2

class TestCase(unittest.TestCase):

    def __init__(self, methodName) -> None:
        super().__init__(methodName)
        
        myServicer = MyLibraryServicer()
        servicers = {
            mylibrary_pb2.DESCRIPTOR.services_by_name['MyLibrary']: myServicer
        }
        self.test_server = server_from_dictionary(
            servicers, strict_real_time())

    def test_search(self):
        request = mylibrary_pb2.Request(
            id=2,
        )
        method = self.test_server.invoke_unary_unary(
            method_descriptor=(mylibrary_pb2.DESCRIPTOR
                .services_by_name['Library']
                .methods_by_name['Search']),
            invocation_metadata={},
            request=request, timeout=1)

        response, metadata, code, details = method.termination()
        self.assertTrue(bool(response.status))
        self.assertEqual(code, StatusCode.OK)

if __name__ == '__main__':
    unittest.main()

Answer 2

I find pytest-grpc is easy to follow and get it works in few minutes.

src: https://pypi.org/project/pytest-grpc/