@responses.activate
def test_multipart_upload(client, test_file_definition):
    responses.add(
        responses.POST,
        url=gen_url(<some_endpoint>),
        json=1,
    )
    client.multipart_upload(...)

~#@❯ pytest -x --no-cov -k test_multipart_upload
Test session starts (platform: win32, Python 3.11.8, pytest 7.4.0, pytest-sugar 1.0.0)
rootdir: C:\Users\<REDACTED>
configfile: pytest.ini
testpaths: tests
plugins: anyio-4.3.0, nbmake-1.5.3, cov-4.1.0, icdiff-0.9, sugar-1.0.0, timeout-2.3.1


―――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――― test_create_new_version ―――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――― 

client = Client(dummy@unknown(http://test:54422))>
tmp_path = WindowsPath('C:/Users/<REDACTED>/pytest-442/test_multipart_upload0')

    @responses.activate
    def test_multipart_upload(client, tmp_path):
        file_path = tmp_path / "test_data.txt"
        write_file(file_path)  # 1 kB

        responses.add(
            responses.POST,
            url=gen_url(<some_endpoint>),
            match=[
                responses.matchers.multipart_matcher({"file_name": b""})
                ],
            json=1,
        )
>       client.multipart_upload(...)

C:\Users\<REDACTED>\tests\client\test_multipart_upload.py
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
C:\Users\<REDACTED>\envs\mylib311\Lib\site-packages\responses\__init__.py:1173: in send
    return self._on_request(adapter, request, **kwargs)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <responses.RequestsMock object at 0x000002AAF71E2B10>, adapter = <requests.adapters.HTTPAdapter object at 0x000002AAF743D210>, request = <PreparedRequest [POST]>, retries = None
kwargs = {'cert': None, 'proxies': OrderedDict(), 'stream': False, 'timeout': None, ...}, match = None
match_failed_reasons = ['multipart/form-data doesn\'t match. Request body differs. <generator object chunk_file_for_upload at 0x000002AAF73C0...: form-data; name="file_name"; filename="file_name"\\r\\n\\r\\n\\r\\n--a5d476d4-c8cc-43cc-bf88-6b8246dadfa1--\\r\\n\'']
resp_callback = None
error_msg = 'Connection refused by Responses - the call doesn\'t match any registered mock.\n\nRequest: \n- POST http://test:54422... form-data; name="file_name"; filename="file_name"\\r\\n\\r\\n\\r\\n--a5d476d4-c8cc-43cc-bf88-6b8246dadfa1--\\r\\n\'\n'
i = 0, m = <Response(url='http://test:54422/<some_endpoint>' status=200 content_type='application/json' headers='null')>

    def _on_request(
        self,
        adapter: "HTTPAdapter",
        request: "PreparedRequest",
        *,
        retries: Optional["_Retry"] = None,
        **kwargs: Any,
    ) -> "models.Response":
        # add attributes params and req_kwargs to 'request' object for further match comparison
        # original request object does not have these attributes
        request.params = self._parse_request_params(request.path_url)  # type: ignore[attr-defined]
        request.req_kwargs = kwargs  # type: ignore[attr-defined]
        request_url = str(request.url)

        match, match_failed_reasons = self._find_match(request)
        resp_callback = self.response_callback

        if match is None:
            if any(
                [
                    p.match(request_url)
                    if isinstance(p, Pattern)
                    else request_url.startswith(p)
                    for p in self.passthru_prefixes
                ]
            ):
                logger.info("request.allowed-passthru", extra={"url": request_url})
                return self._real_send(adapter, request, **kwargs)  # type: ignore

            error_msg = (
                "Connection refused by Responses - the call doesn't "
                "match any registered mock.\n\n"
                "Request: \n"
                f"- {request.method} {request_url}\n\n"
                "Available matches:\n"
            )
            for i, m in enumerate(self.registered()):
                error_msg += "- {} {} {}\n".format(
                    m.method, m.url, match_failed_reasons[i]
                )

            if self.passthru_prefixes:
                error_msg += "Passthru prefixes:\n"
                for p in self.passthru_prefixes:
                    error_msg += f"- {p}\n"

            response = ConnectionError(error_msg)
            response.request = request

            self._calls.add(request, response)
>           raise response
E           requests.exceptions.ConnectionError: Connection refused by Responses - the call doesn't match any registered mock.
E
E           Request: 
E           - POST http://test:54422/<some_endpoint>?complete=False&encoding=utf-16
E
E           Available matches:
E           - POST http://test:54422/<some_endpoint> multipart/form-data doesn't match. Request body differs. <generator object chunk_file_for_upload at 0x000002AAF73C0DC0> aren't equal b'--a5d476d4-c8cc-43cc-bf88-6b8246dadfa1\r\nContent-Disposition: form-data; name="file_name"; filename="file_name"\r\n\r\n\r\n--a5d476d4-c8cc-43cc-bf88-6b8246dadfa1--\r\n'

C:\Users\<REDACTED>\envs\mylib311\Lib\site-packages\responses\__init__.py:1100: ConnectionError