standard-tests: migrate to pytest-recording (#31425)

Co-authored-by: Eugene Yurtsev <eyurtsev@gmail.com>

libs/partners/anthropic/tests/cassettes/TestAnthropicStandard_test_stream_time.yaml.gz

@@ -1 +0,0 @@
-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

libs/partners/anthropic/tests/conftest.py

@@ -1,7 +1,7 @@
 from typing import Any
 
 import pytest
-from langchain_tests.conftest import YamlGzipSerializer
+from langchain_tests.conftest import CustomPersister, CustomSerializer
 from langchain_tests.conftest import _base_vcr_config as _base_vcr_config
 from vcr import VCR  # type: ignore[import-untyped]
 
@@ -32,9 +32,6 @@ def vcr_config(_base_vcr_config: dict) -> dict:  # noqa: F811
     return config
 
 
-@pytest.fixture
+def pytest_recording_configure(config: dict, vcr: VCR) -> None:
-def vcr(vcr_config: dict) -> VCR:
+    vcr.register_persister(CustomPersister())
-    """Override the default vcr fixture to include custom serializers"""
+    vcr.register_serializer("yaml.gz", CustomSerializer())
-    my_vcr = VCR(**vcr_config)
-    my_vcr.register_serializer("yaml.gz", YamlGzipSerializer)
-    return my_vcr

libs/partners/anthropic/uv.lock

@@ -502,7 +502,7 @@ typing = [
 
 [[package]]
 name = "langchain-core"
-version = "0.3.62"
+version = "0.3.63"
 source = { editable = "../../core" }
 dependencies = [
     { name = "jsonpatch" },
@@ -571,8 +571,8 @@ dependencies = [
     { name = "pytest-asyncio" },
     { name = "pytest-benchmark" },
     { name = "pytest-codspeed" },
+    { name = "pytest-recording" },
     { name = "pytest-socket" },
-    { name = "pytest-vcr" },
     { name = "syrupy" },
     { name = "vcrpy" },
 ]
@@ -587,8 +587,8 @@ requires-dist = [
     { name = "pytest-asyncio", specifier = ">=0.20,<1" },
     { name = "pytest-benchmark" },
     { name = "pytest-codspeed" },
+    { name = "pytest-recording" },
     { name = "pytest-socket", specifier = ">=0.6.0,<1" },
-    { name = "pytest-vcr" },
     { name = "syrupy", specifier = ">=4,<5" },
     { name = "vcrpy", specifier = ">=7.0" },
 ]
@@ -1339,6 +1339,19 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/f2/3b/b26f90f74e2986a82df6e7ac7e319b8ea7ccece1caec9f8ab6104dc70603/pytest_mock-3.14.0-py3-none-any.whl", hash = "sha256:0b72c38033392a5f4621342fe11e9219ac11ec9d375f8e2a0c164539e0d70f6f", size = 9863 },
 ]
 
+[[package]]
+name = "pytest-recording"
+version = "0.13.4"
+source = { registry = "https://pypi.org/simple" }
+dependencies = [
+    { name = "pytest" },
+    { name = "vcrpy" },
+]
+sdist = { url = "https://files.pythonhosted.org/packages/32/9c/f4027c5f1693847b06d11caf4b4f6bb09f22c1581ada4663877ec166b8c6/pytest_recording-0.13.4.tar.gz", hash = "sha256:568d64b2a85992eec4ae0a419c855d5fd96782c5fb016784d86f18053792768c", size = 26576 }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/42/c2/ce34735972cc42d912173e79f200fe66530225190c06655c5632a9d88f1e/pytest_recording-0.13.4-py3-none-any.whl", hash = "sha256:ad49a434b51b1c4f78e85b1e6b74fdcc2a0a581ca16e52c798c6ace971f7f439", size = 13723 },
+]
+
 [[package]]
 name = "pytest-retry"
 version = "1.7.0"
@@ -1375,19 +1388,6 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/03/27/14af9ef8321f5edc7527e47def2a21d8118c6f329a9342cc61387a0c0599/pytest_timeout-2.3.1-py3-none-any.whl", hash = "sha256:68188cb703edfc6a18fad98dc25a3c61e9f24d644b0b70f33af545219fc7813e", size = 14148 },
 ]
 
-[[package]]
-name = "pytest-vcr"
-version = "1.0.2"
-source = { registry = "https://pypi.org/simple" }
-dependencies = [
-    { name = "pytest" },
-    { name = "vcrpy" },
-]
-sdist = { url = "https://files.pythonhosted.org/packages/1a/60/104c619483c1a42775d3f8b27293f1ecfc0728014874d065e68cb9702d49/pytest-vcr-1.0.2.tar.gz", hash = "sha256:23ee51b75abbcc43d926272773aae4f39f93aceb75ed56852d0bf618f92e1896", size = 3810 }
-wheels = [
-    { url = "https://files.pythonhosted.org/packages/9d/d3/ff520d11e6ee400602711d1ece8168dcfc5b6d8146fb7db4244a6ad6a9c3/pytest_vcr-1.0.2-py2.py3-none-any.whl", hash = "sha256:2f316e0539399bea0296e8b8401145c62b6f85e9066af7e57b6151481b0d6d9c", size = 4137 },
-]
-
 [[package]]
 name = "pytest-watcher"
 version = "0.4.3"

libs/partners/openai/tests/conftest.py

@@ -1,7 +1,7 @@
 from typing import Any
 
 import pytest
-from langchain_tests.conftest import YamlGzipSerializer
+from langchain_tests.conftest import CustomPersister, CustomSerializer
 from langchain_tests.conftest import _base_vcr_config as _base_vcr_config
 from vcr import VCR  # type: ignore[import-untyped]
 
@@ -13,6 +13,7 @@ _EXTRA_HEADERS = [
 
 
 def remove_request_headers(request: Any) -> Any:
+    """Remove sensitive headers from the request."""
     for k in request.headers:
         request.headers[k] = "**REDACTED**"
     request.uri = "**REDACTED**"
@@ -20,6 +21,7 @@ def remove_request_headers(request: Any) -> Any:
 
 
 def remove_response_headers(response: dict) -> dict:
+    """Remove sensitive headers from the response."""
     for k in response["headers"]:
         response["headers"][k] = "**REDACTED**"
     return response
@@ -27,22 +29,16 @@ def remove_response_headers(response: dict) -> dict:
 
 @pytest.fixture(scope="session")
 def vcr_config(_base_vcr_config: dict) -> dict:  # noqa: F811
-    """
+    """Extend the default configuration coming from langchain_tests."""
-    Extend the default configuration coming from langchain_tests.
-    """
     config = _base_vcr_config.copy()
     config.setdefault("filter_headers", []).extend(_EXTRA_HEADERS)
     config["before_record_request"] = remove_request_headers
     config["before_record_response"] = remove_response_headers
     config["serializer"] = "yaml.gz"
     config["path_transformer"] = VCR.ensure_suffix(".yaml.gz")
-
     return config
 
 
-@pytest.fixture
+def pytest_recording_configure(config: dict, vcr: VCR) -> None:
-def vcr(vcr_config: dict) -> VCR:
+    vcr.register_persister(CustomPersister())
-    """Override the default vcr fixture to include custom serializers"""
+    vcr.register_serializer("yaml.gz", CustomSerializer())
-    my_vcr = VCR(**vcr_config)
-    my_vcr.register_serializer("yaml.gz", YamlGzipSerializer)
-    return my_vcr

libs/partners/openai/uv.lock

@@ -479,7 +479,7 @@ wheels = [
 
 [[package]]
 name = "langchain-core"
-version = "0.3.62"
+version = "0.3.63"
 source = { editable = "../../core" }
 dependencies = [
     { name = "jsonpatch" },
@@ -637,8 +637,8 @@ dependencies = [
     { name = "pytest-asyncio" },
     { name = "pytest-benchmark" },
     { name = "pytest-codspeed" },
+    { name = "pytest-recording" },
     { name = "pytest-socket" },
-    { name = "pytest-vcr" },
     { name = "syrupy" },
     { name = "vcrpy" },
 ]
@@ -653,8 +653,8 @@ requires-dist = [
     { name = "pytest-asyncio", specifier = ">=0.20,<1" },
     { name = "pytest-benchmark" },
     { name = "pytest-codspeed" },
+    { name = "pytest-recording" },
     { name = "pytest-socket", specifier = ">=0.6.0,<1" },
-    { name = "pytest-vcr" },
     { name = "syrupy", specifier = ">=4,<5" },
     { name = "vcrpy", specifier = ">=7.0" },
 ]
@@ -1514,6 +1514,19 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/f2/3b/b26f90f74e2986a82df6e7ac7e319b8ea7ccece1caec9f8ab6104dc70603/pytest_mock-3.14.0-py3-none-any.whl", hash = "sha256:0b72c38033392a5f4621342fe11e9219ac11ec9d375f8e2a0c164539e0d70f6f", size = 9863 },
 ]
 
+[[package]]
+name = "pytest-recording"
+version = "0.13.4"
+source = { registry = "https://pypi.org/simple" }
+dependencies = [
+    { name = "pytest" },
+    { name = "vcrpy" },
+]
+sdist = { url = "https://files.pythonhosted.org/packages/32/9c/f4027c5f1693847b06d11caf4b4f6bb09f22c1581ada4663877ec166b8c6/pytest_recording-0.13.4.tar.gz", hash = "sha256:568d64b2a85992eec4ae0a419c855d5fd96782c5fb016784d86f18053792768c", size = 26576 }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/42/c2/ce34735972cc42d912173e79f200fe66530225190c06655c5632a9d88f1e/pytest_recording-0.13.4-py3-none-any.whl", hash = "sha256:ad49a434b51b1c4f78e85b1e6b74fdcc2a0a581ca16e52c798c6ace971f7f439", size = 13723 },
+]
+
 [[package]]
 name = "pytest-retry"
 version = "1.7.0"
@@ -1538,19 +1551,6 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/19/58/5d14cb5cb59409e491ebe816c47bf81423cd03098ea92281336320ae5681/pytest_socket-0.7.0-py3-none-any.whl", hash = "sha256:7e0f4642177d55d317bbd58fc68c6bd9048d6eadb2d46a89307fa9221336ce45", size = 6754 },
 ]
 
-[[package]]
-name = "pytest-vcr"
-version = "1.0.2"
-source = { registry = "https://pypi.org/simple" }
-dependencies = [
-    { name = "pytest" },
-    { name = "vcrpy" },
-]
-sdist = { url = "https://files.pythonhosted.org/packages/1a/60/104c619483c1a42775d3f8b27293f1ecfc0728014874d065e68cb9702d49/pytest-vcr-1.0.2.tar.gz", hash = "sha256:23ee51b75abbcc43d926272773aae4f39f93aceb75ed56852d0bf618f92e1896", size = 3810 }
-wheels = [
-    { url = "https://files.pythonhosted.org/packages/9d/d3/ff520d11e6ee400602711d1ece8168dcfc5b6d8146fb7db4244a6ad6a9c3/pytest_vcr-1.0.2-py2.py3-none-any.whl", hash = "sha256:2f316e0539399bea0296e8b8401145c62b6f85e9066af7e57b6151481b0d6d9c", size = 4137 },
-]
-
 [[package]]
 name = "pytest-watcher"
 version = "0.4.3"

libs/standard-tests/langchain_tests/conftest.py

@@ -1,25 +1,85 @@
-import base64
 import gzip
+from os import PathLike
+from pathlib import Path
+from typing import Union
 
 import pytest
-from vcr import VCR  # type: ignore[import-untyped]
+import yaml
-from vcr.serializers import yamlserializer  # type: ignore[import-untyped]
+from vcr import VCR
+from vcr.persisters.filesystem import CassetteNotFoundError
+from vcr.request import Request
 
 
-class YamlGzipSerializer:
+class CustomSerializer:
-    @staticmethod
+    """Custom serializer for VCR cassettes using YAML and gzip.
-    def serialize(cassette_dict: dict) -> str:
+
-        raw = yamlserializer.serialize(cassette_dict).encode("utf-8")
+    We're using a custom serializer to avoid the default yaml serializer
-        compressed = gzip.compress(raw)
+    used by VCR, which is not designed to be safe for untrusted input.
-        return base64.b64encode(compressed).decode("ascii")
+
+    This step is an extra precaution necessary because the cassette files
+    are in compressed YAML format, which makes it more difficult to inspect
+    their contents during development or debugging.
+    """
 
     @staticmethod
-    def deserialize(data: str) -> dict:
+    def serialize(cassette_dict: dict) -> bytes:
-        compressed = base64.b64decode(data.encode("ascii"))
+        """Convert cassette to YAML and compress it."""
-        text = gzip.decompress(compressed).decode("utf-8")
+        cassette_dict["requests"] = [
-        return yamlserializer.deserialize(text)
+            request._to_dict() for request in cassette_dict["requests"]
+        ]
+        yml = yaml.safe_dump(cassette_dict)
+        return gzip.compress(yml.encode("utf-8"))
+
+    @staticmethod
+    def deserialize(data: bytes) -> dict:
+        """Decompress data and convert it from YAML."""
+        text = gzip.decompress(data).decode("utf-8")
+        cassette = yaml.safe_load(text)
+        cassette["requests"] = [
+            Request._from_dict(request) for request in cassette["requests"]
+        ]
+        return cassette
 
 
+class CustomPersister:
+    """A custom persister for VCR that uses the CustomSerializer."""
+
+    @classmethod
+    def load_cassette(
+        cls, cassette_path: Union[str, PathLike[str]], serializer: CustomSerializer
+    ) -> tuple[dict, dict]:
+        """Load a cassette from a file."""
+        # If cassette path is already Path this is a no-op
+        cassette_path = Path(cassette_path)
+        if not cassette_path.is_file():
+            raise CassetteNotFoundError(
+                f"Cassette file {cassette_path} does not exist."
+            )
+        with cassette_path.open(mode="rb") as f:
+            data = f.read()
+        deser = serializer.deserialize(data)
+        return deser["requests"], deser["responses"]
+
+    @staticmethod
+    def save_cassette(
+        cassette_path: Union[str, PathLike[str]],
+        cassette_dict: dict,
+        serializer: CustomSerializer,
+    ) -> None:
+        """Save a cassette to a file."""
+        data = serializer.serialize(cassette_dict)
+        # if cassette path is already Path this is no operation
+        cassette_path = Path(cassette_path)
+        cassette_folder = cassette_path.parent
+        if not cassette_folder.exists():
+            cassette_folder.mkdir(parents=True)
+        with cassette_path.open("wb") as f:
+            f.write(data)
+
+
+# A list of headers that should be filtered out of the cassettes.
+# These are typically associated with sensitive information and should
+# not be stored in cassettes.
 _BASE_FILTER_HEADERS = [
     ("authorization", "PLACEHOLDER"),
     ("x-api-key", "PLACEHOLDER"),
@@ -29,14 +89,15 @@ _BASE_FILTER_HEADERS = [
 
 @pytest.fixture(scope="session")
 def _base_vcr_config() -> dict:
-    """
+    """Configuration that every cassette will receive.
-    Configuration that every cassette will receive.
+
     (Anything permitted by vcr.VCR(**kwargs) can be put here.)
     """
     return {
         "record_mode": "once",
         "filter_headers": _BASE_FILTER_HEADERS.copy(),
-        "match_on": ["method", "scheme", "host", "port", "path", "query"],
+        "match_on": ["method", "uri", "body"],
+        "allow_playback_repeats": True,
         "decode_compressed_response": True,
         "cassette_library_dir": "tests/cassettes",
         "path_transformer": VCR.ensure_suffix(".yaml"),

libs/standard-tests/langchain_tests/integration_tests/chat_models.py

@@ -6,7 +6,6 @@ from unittest.mock import MagicMock
 
 import httpx
 import pytest
-import vcr  # type: ignore[import-untyped]
 from langchain_core._api import warn_deprecated
 from langchain_core.callbacks import BaseCallbackHandler
 from langchain_core.language_models import BaseChatModel, GenericFakeChatModel
@@ -31,6 +30,7 @@ from pydantic.v1 import BaseModel as BaseModelV1
 from pydantic.v1 import Field as FieldV1
 from pytest_benchmark.fixture import BenchmarkFixture  # type: ignore[import-untyped]
 from typing_extensions import Annotated, TypedDict
+from vcr.cassette import Cassette
 
 from langchain_tests.unit_tests.chat_models import (
     ChatModelTests,
@@ -592,7 +592,7 @@ class ChatModelIntegrationTests(ChatModelTests):
                     :caption: tests/conftest.py
 
                     import pytest
-                    from langchain_tests.conftest import YamlGzipSerializer
+                    from langchain_tests.conftest import CustomPersister, CustomSerializer
                     from langchain_tests.conftest import _base_vcr_config as _base_vcr_config
                     from vcr import VCR
 
@@ -621,24 +621,26 @@ class ChatModelIntegrationTests(ChatModelTests):
                         return config
 
 
-                    @pytest.fixture
+                    def pytest_recording_configure(config: dict, vcr: VCR) -> None:
-                    def vcr(vcr_config: dict) -> VCR:
+                        vcr.register_persister(CustomPersister())
-                        \"\"\"Override the default vcr fixture to include custom serializers\"\"\"
+                        vcr.register_serializer("yaml.gz", CustomSerializer())
-                        my_vcr = VCR(**vcr_config)
+
-                        my_vcr.register_serializer("yaml.gz", YamlGzipSerializer)
-                        return my_vcr
 
                 You can inspect the contents of the compressed cassettes (e.g., to
-                ensure no sensitive information is recorded) using the serializer:
+                ensure no sensitive information is recorded) using
+
+                .. code-block:: bash
+
+                    gunzip -k /path/to/tests/cassettes/TestClass_test.yaml.gz
+
+                or by using the serializer:
 
                 .. code-block:: python
 
-                    from langchain_tests.conftest import YamlGzipSerializer
+                    from langchain_tests.conftest import CustomPersister, CustomSerializer
 
-                    with open("/path/to/tests/cassettes/TestClass_test.yaml.gz", "r") as f:
+                    cassette_path = "/path/to/tests/cassettes/TestClass_test.yaml.gz"
-                        data = f.read()
+                    requests, responses = CustomPersister().load_cassette(path, CustomSerializer())
-
-                    YamlGzipSerializer.deserialize(data)
 
         3. Run tests to generate VCR cassettes.
 
@@ -2826,8 +2828,9 @@ class ChatModelIntegrationTests(ChatModelTests):
         assert isinstance(response, AIMessage)
 
     @pytest.mark.benchmark
+    @pytest.mark.vcr
     def test_stream_time(
-        self, model: BaseChatModel, benchmark: BenchmarkFixture, vcr: vcr.VCR
+        self, model: BaseChatModel, benchmark: BenchmarkFixture, vcr: Cassette
     ) -> None:
         """Test that streaming does not introduce undue overhead.
 
@@ -2857,11 +2860,12 @@ class ChatModelIntegrationTests(ChatModelTests):
             pytest.skip("VCR not set up.")
 
         def _run() -> None:
-            cassette_name = f"{self.__class__.__name__}_test_stream_time"
-            with vcr.use_cassette(cassette_name, record_mode="once"):
             for _ in model.stream("Write a story about a cat."):
                 pass
 
+        if not vcr.responses:
+            _run()
+        else:
             benchmark(_run)
 
     def invoke_with_audio_input(self, *, stream: bool = False) -> AIMessage:

libs/standard-tests/langchain_tests/unit_tests/chat_models.py

@@ -693,7 +693,7 @@ class ChatModelUnitTests(ChatModelTests):
                     :caption: tests/conftest.py
 
                     import pytest
-                    from langchain_tests.conftest import YamlGzipSerializer
+                    from langchain_tests.conftest import CustomPersister, CustomSerializer
                     from langchain_tests.conftest import _base_vcr_config as _base_vcr_config
                     from vcr import VCR
 
@@ -722,24 +722,26 @@ class ChatModelUnitTests(ChatModelTests):
                         return config
 
 
-                    @pytest.fixture
+                    def pytest_recording_configure(config: dict, vcr: VCR) -> None:
-                    def vcr(vcr_config: dict) -> VCR:
+                        vcr.register_persister(CustomPersister())
-                        \"\"\"Override the default vcr fixture to include custom serializers\"\"\"
+                        vcr.register_serializer("yaml.gz", CustomSerializer())
-                        my_vcr = VCR(**vcr_config)
+
-                        my_vcr.register_serializer("yaml.gz", YamlGzipSerializer)
-                        return my_vcr
 
                 You can inspect the contents of the compressed cassettes (e.g., to
-                ensure no sensitive information is recorded) using the serializer:
+                ensure no sensitive information is recorded) using
+
+                .. code-block:: bash
+
+                    gunzip -k /path/to/tests/cassettes/TestClass_test.yaml.gz
+
+                or by using the serializer:
 
                 .. code-block:: python
 
-                    from langchain_tests.conftest import YamlGzipSerializer
+                    from langchain_tests.conftest import CustomPersister, CustomSerializer
 
-                    with open("/path/to/tests/cassettes/TestClass_test.yaml.gz", "r") as f:
+                    cassette_path = "/path/to/tests/cassettes/TestClass_test.yaml.gz"
-                        data = f.read()
+                    requests, responses = CustomPersister().load_cassette(path, CustomSerializer())
-
-                    YamlGzipSerializer.deserialize(data)
 
         3. Run tests to generate VCR cassettes.
 

libs/standard-tests/pyproject.toml

@@ -15,7 +15,7 @@ dependencies = [
     "pytest-socket<1,>=0.6.0",
     "pytest-benchmark",
     "pytest-codspeed",
-    "pytest-vcr",
+    "pytest-recording",
     "vcrpy>=7.0",
     "numpy>=1.26.2; python_version<'3.13'",
     "numpy>=2.1.0; python_version>='3.13'",
@@ -42,6 +42,15 @@ langchain-core = { path = "../core", editable = true }
 [tool.mypy]
 disallow_untyped_defs = "True"
 
+[[tool.mypy.overrides]]
+module = "yaml"
+ignore_missing_imports = true
+
+[[tool.mypy.overrides]]
+module = "vcr.*"
+ignore_missing_imports = true
+
+
 [tool.ruff]
 target-version = "py39"
 

libs/standard-tests/uv.lock

@@ -304,7 +304,7 @@ wheels = [
 
 [[package]]
 name = "langchain-core"
-version = "0.3.60"
+version = "0.3.63"
 source = { editable = "../core" }
 dependencies = [
     { name = "jsonpatch" },
@@ -373,8 +373,8 @@ dependencies = [
     { name = "pytest-asyncio" },
     { name = "pytest-benchmark" },
     { name = "pytest-codspeed" },
+    { name = "pytest-recording" },
     { name = "pytest-socket" },
-    { name = "pytest-vcr" },
     { name = "syrupy" },
     { name = "vcrpy" },
 ]
@@ -404,8 +404,8 @@ requires-dist = [
     { name = "pytest-asyncio", specifier = ">=0.20,<1" },
     { name = "pytest-benchmark" },
     { name = "pytest-codspeed" },
+    { name = "pytest-recording" },
     { name = "pytest-socket", specifier = ">=0.6.0,<1" },
-    { name = "pytest-vcr" },
     { name = "syrupy", specifier = ">=4,<5" },
     { name = "vcrpy", specifier = ">=7.0" },
 ]
@@ -1153,6 +1153,19 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/f1/9b/952c70bd1fae9baa58077272e7f191f377c86d812263c21b361195e125e6/pytest_codspeed-3.2.0-py3-none-any.whl", hash = "sha256:54b5c2e986d6a28e7b0af11d610ea57bd5531cec8326abe486f1b55b09d91c39", size = 15007 },
 ]
 
+[[package]]
+name = "pytest-recording"
+version = "0.13.4"
+source = { registry = "https://pypi.org/simple" }
+dependencies = [
+    { name = "pytest" },
+    { name = "vcrpy" },
+]
+sdist = { url = "https://files.pythonhosted.org/packages/32/9c/f4027c5f1693847b06d11caf4b4f6bb09f22c1581ada4663877ec166b8c6/pytest_recording-0.13.4.tar.gz", hash = "sha256:568d64b2a85992eec4ae0a419c855d5fd96782c5fb016784d86f18053792768c", size = 26576 }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/42/c2/ce34735972cc42d912173e79f200fe66530225190c06655c5632a9d88f1e/pytest_recording-0.13.4-py3-none-any.whl", hash = "sha256:ad49a434b51b1c4f78e85b1e6b74fdcc2a0a581ca16e52c798c6ace971f7f439", size = 13723 },
+]
+
 [[package]]
 name = "pytest-socket"
 version = "0.7.0"
@@ -1165,19 +1178,6 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/19/58/5d14cb5cb59409e491ebe816c47bf81423cd03098ea92281336320ae5681/pytest_socket-0.7.0-py3-none-any.whl", hash = "sha256:7e0f4642177d55d317bbd58fc68c6bd9048d6eadb2d46a89307fa9221336ce45", size = 6754 },
 ]
 
-[[package]]
-name = "pytest-vcr"
-version = "1.0.2"
-source = { registry = "https://pypi.org/simple" }
-dependencies = [
-    { name = "pytest" },
-    { name = "vcrpy" },
-]
-sdist = { url = "https://files.pythonhosted.org/packages/1a/60/104c619483c1a42775d3f8b27293f1ecfc0728014874d065e68cb9702d49/pytest-vcr-1.0.2.tar.gz", hash = "sha256:23ee51b75abbcc43d926272773aae4f39f93aceb75ed56852d0bf618f92e1896", size = 3810 }
-wheels = [
-    { url = "https://files.pythonhosted.org/packages/9d/d3/ff520d11e6ee400602711d1ece8168dcfc5b6d8146fb7db4244a6ad6a9c3/pytest_vcr-1.0.2-py2.py3-none-any.whl", hash = "sha256:2f316e0539399bea0296e8b8401145c62b6f85e9066af7e57b6151481b0d6d9c", size = 4137 },
-]
-
 [[package]]
 name = "pyyaml"
 version = "6.0.2"