How to test httpx with trio and respx

Hi Lundberg, I am working on a project on httpx using trio async libray. Following your documentation, I ended up with a test like this:

    @pytest.mark.trio
    async def test_should_do_something(trio_tmp_path):
        async with respx.mock:
            async with httpx.AsyncClient() as client:
                analyser = RobotsAnalyzer(
                    user_agent='Mozilla/5.0',
                    robots_cache=trio_tmp_path,
                    http_client=client,
                    robots_mapping_lock=robots_mapping_lock_mock,
                    delay_mapping_lock=delay_mapping_lock_mock
                )
                respx.get('/robots.txt', content=httpx.ConnectTimeout())
                assert await analyser.can_fetch('http://example.com/path') is False

but I have this weird error, I don’t know if there is a tip to avoid the issue.

value = <trio.Nursery object at 0x051E4EB0>

    async def yield_(value=None):
>       return await _yield_(value)

C:\Users\rolla\AppData\Local\pypoetry\Cache\virtualenvs\scalpel-HJDWBcSE-py3.8\lib\site-packages\async_generator\_impl.py:106: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
C:\Users\rolla\AppData\Local\pypoetry\Cache\virtualenvs\scalpel-HJDWBcSE-py3.8\lib\site-packages\async_generator\_impl.py:99: in _yield_
    return (yield _wrap(value))
test_robots.py:104: in test_should_return_false_when_host_does_not_exist
    assert await analyser.can_fetch('http://example.com/path') is False
..\..\scalpel\trionic\robots.py:53: in can_fetch
    response = await self._http_client.get(f'{robots_url}')
C:\Users\rolla\AppData\Local\pypoetry\Cache\virtualenvs\scalpel-HJDWBcSE-py3.8\lib\site-packages\httpx\_client.py:1224: in get
    return await self.request(
C:\Users\rolla\AppData\Local\pypoetry\Cache\virtualenvs\scalpel-HJDWBcSE-py3.8\lib\site-packages\httpx\_client.py:1085: in request
    response = await self.send(
C:\Users\rolla\AppData\Local\pypoetry\Cache\virtualenvs\scalpel-HJDWBcSE-py3.8\lib\site-packages\respx\mocks.py:162: in unbound_async_send
    return await self.__AsyncClient__send__spy(client, request, **kwargs)
C:\Users\rolla\AppData\Local\pypoetry\Cache\virtualenvs\scalpel-HJDWBcSE-py3.8\lib\site-packages\respx\mocks.py:530: in __AsyncClient__send__spy
    with self._patch_dispatcher(client.dispatch, request) as capture:
C:\Users\rolla\AppData\Local\Programs\Python\Python38-32\lib\contextlib.py:113: in __enter__
    return next(self.gen)
C:\Users\rolla\AppData\Local\pypoetry\Cache\virtualenvs\scalpel-HJDWBcSE-py3.8\lib\site-packages\respx\mocks.py:472: in _patch_dispatcher
    httpx_mock, pattern, response = self._match(request)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

self = <respx.mocks.HTTPXMock object at 0x051363E8>
request = <Request('GET', 'http://example.com/robots.txt')>

    def _match(
        self, request: Request
    ) -> typing.Tuple[
        "HTTPXMock", typing.Optional[RequestPattern], typing.Optional[ResponseTemplate]
    ]:
        used_mock = self
        matched_pattern: typing.Optional[RequestPattern] = None
        matched_pattern_index: typing.Optional[int] = None
        response: typing.Optional[ResponseTemplate] = None
    
        # Iterate all started mockers and their patterns
        for httpx_mock in self._mocks:
            patterns = httpx_mock._patterns
    
            for i, pattern in enumerate(patterns):
                match = pattern.match(request)
                if not match:
                    continue
    
                if matched_pattern_index is not None:
                    # Multiple matches found, drop and use the first one
                    patterns.pop(matched_pattern_index)
                    break
    
                used_mock = httpx_mock
                matched_pattern = pattern
                matched_pattern_index = i
    
                if isinstance(match, ResponseTemplate):
                    # Mock response
                    response = match
                elif isinstance(match, Request):
                    # Pass-through request
                    response = None
                else:
                    raise ValueError(
                        (
                            "Matched request pattern must return either a "
                            'ResponseTemplate or a Request, got "{}"'
                        ).format(type(match))
                    )
    
            if matched_pattern:
                break
    
        if matched_pattern is None:
            # Assert we always get a pattern match, if check is enabled
            allows_unmocked = tuple(m for m in self._mocks if not m._assert_all_mocked)
>           assert allows_unmocked, f"RESPX: {request!r} not mocked!"
E           AssertionError: RESPX: <Request('GET', 'http://example.com/robots.txt')> not mocked!

My environment

• windows 10
• python3.8
• trio 0.13.0
• pytest-trio 0.5.2
• respx 0.10.1

Best regards

[lewoudar]

Hi lundberg, thank you for the tip. I don’t really know where I made a mistake but re-using your last example works for me.

Again thanks 😃

[lundberg]

I re-read your issue and I think I was to fast writing my last answer 😉

When configuring the respx mock object with base_url we need to add the request patterns to the context manager instance.

Try this:

async with respx.mock(base_url="http://example.com") as respx_mock:
    ...
    respx_mock.get('/robots.txt', content=httpx.ConnectTimeout())  # NOTE: mock instance
    ....

…hopes this was the issue and helps you.