community: Use Blockbuster to detect blocking calls in asyncio during tests (#29609)

Same as https://github.com/langchain-ai/langchain/pull/29043 for
langchain-community.

**Dependencies:**
- blockbuster (test)

**Twitter handle:** cbornet_

Co-authored-by: Erick Friis <erick@langchain.dev>

libs/community/langchain_community/utils/openai.py

@@ -1,10 +1,12 @@
 from __future__ import annotations
 
+import functools
 from importlib.metadata import version
 
 from packaging.version import parse
 
 
+@functools.cache
 def is_openai_v1() -> bool:
     """Return whether OpenAI API is v1 or more."""
     _version = parse(version("openai"))

libs/community/pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "pdm.backend"
 
 [project]
 authors = []
-license = {text = "MIT"}
+license = { text = "MIT" }
 requires-python = "<4.0,>=3.9"
 dependencies = [
     "langchain-core<1.0.0,>=0.3.34",
@@ -48,6 +48,7 @@ test = [
     "syrupy<5.0.0,>=4.0.2",
     "requests-mock<2.0.0,>=1.11.0",
     "pytest-xdist<4.0.0,>=3.6.1",
+    "blockbuster<1.6,>=1.5.13",
     "cffi<1.17.1; python_version < \"3.10\"",
     "cffi; python_version >= \"3.10\"",
     "langchain-core @ file:///${PROJECT_ROOT}/../core",
@@ -55,13 +56,8 @@ test = [
     "langchain-tests @ file:///${PROJECT_ROOT}/../standard-tests",
     "toml>=0.10.2",
 ]
-codespell = [
+codespell = ["codespell<3.0.0,>=2.2.0"]
-    "codespell<3.0.0,>=2.2.0",
+test_integration = ["pytest-vcr<2.0.0,>=1.0.2", "vcrpy<7,>=6"]
-]
-test_integration = [
-    "pytest-vcr<2.0.0,>=1.0.2",
-    "vcrpy<7,>=6",
-]
 lint = [
     "ruff<0.6,>=0.5",
     "cffi<1.17.1; python_version < \"3.10\"",

libs/community/tests/unit_tests/conftest.py

@@ -1,12 +1,28 @@
 """Configuration for unit tests."""
 
+from collections.abc import Iterator
 from importlib import util
 from typing import Dict, Sequence
 
 import pytest
+from blockbuster import blockbuster_ctx
 from pytest import Config, Function, Parser
 
 
+@pytest.fixture(autouse=True)
+def blockbuster() -> Iterator[None]:
+    with blockbuster_ctx("langchain_community") as bb:
+        (
+            bb.functions["os.stat"]
+            .can_block_in("langchain_community/utils/openai.py", "is_openai_v1")
+            .can_block_in("httpx/_client.py", "_init_transport")
+        )
+        bb.functions["os.path.abspath"].can_block_in(
+            "sqlalchemy/dialects/sqlite/pysqlite.py", "create_connect_args"
+        )
+        yield
+
+
 def pytest_addoption(parser: Parser) -> None:
     """Add custom command line options to pytest."""
     parser.addoption(

libs/community/tests/unit_tests/test_cache.py

@@ -62,20 +62,31 @@ def set_cache_and_teardown(request: FixtureRequest) -> Generator[None, None, Non
         raise ValueError("Cache not set. This should never happen.")
 
 
-async def test_llm_caching() -> None:
+def test_llm_caching() -> None:
     prompt = "How are you?"
     response = "Test response"
     cached_response = "Cached test response"
     llm = FakeListLLM(responses=[response])
     if llm_cache := get_llm_cache():
-        # sync test
         llm_cache.update(
             prompt=prompt,
             llm_string=create_llm_string(llm),
             return_val=[Generation(text=cached_response)],
         )
         assert llm.invoke(prompt) == cached_response
-        # async test
+    else:
+        raise ValueError(
+            "The cache not set. This should never happen, as the pytest fixture "
+            "`set_cache_and_teardown` always sets the cache."
+        )
+
+
+async def test_llm_caching_async() -> None:
+    prompt = "How are you?"
+    response = "Test response"
+    cached_response = "Cached test response"
+    llm = FakeListLLM(responses=[response])
+    if llm_cache := get_llm_cache():
         await llm_cache.aupdate(
             prompt=prompt,
             llm_string=create_llm_string(llm),
@@ -110,14 +121,13 @@ def test_old_sqlite_llm_caching() -> None:
         assert llm.invoke(prompt) == cached_response
 
 
-async def test_chat_model_caching() -> None:
+def test_chat_model_caching() -> None:
     prompt: List[BaseMessage] = [HumanMessage(content="How are you?")]
     response = "Test response"
     cached_response = "Cached test response"
     cached_message = AIMessage(content=cached_response)
     llm = FakeListChatModel(responses=[response])
     if llm_cache := get_llm_cache():
-        # sync test
         llm_cache.update(
             prompt=dumps(prompt),
             llm_string=llm._get_llm_string(),
@@ -126,8 +136,20 @@ async def test_chat_model_caching() -> None:
         result = llm.invoke(prompt)
         assert isinstance(result, AIMessage)
         assert result.content == cached_response
+    else:
+        raise ValueError(
+            "The cache not set. This should never happen, as the pytest fixture "
+            "`set_cache_and_teardown` always sets the cache."
+        )
 
-        # async test
+
+async def test_chat_model_caching_async() -> None:
+    prompt: List[BaseMessage] = [HumanMessage(content="How are you?")]
+    response = "Test response"
+    cached_response = "Cached test response"
+    cached_message = AIMessage(content=cached_response)
+    llm = FakeListChatModel(responses=[response])
+    if llm_cache := get_llm_cache():
         await llm_cache.aupdate(
             prompt=dumps(prompt),
             llm_string=llm._get_llm_string(),
@@ -143,14 +165,13 @@ async def test_chat_model_caching() -> None:
         )
 
 
-async def test_chat_model_caching_params() -> None:
+def test_chat_model_caching_params() -> None:
     prompt: List[BaseMessage] = [HumanMessage(content="How are you?")]
     response = "Test response"
     cached_response = "Cached test response"
     cached_message = AIMessage(content=cached_response)
     llm = FakeListChatModel(responses=[response])
     if llm_cache := get_llm_cache():
-        # sync test
         llm_cache.update(
             prompt=dumps(prompt),
             llm_string=llm._get_llm_string(functions=[]),
@@ -162,8 +183,20 @@ async def test_chat_model_caching_params() -> None:
         assert result.content == cached_response
         assert isinstance(result_no_params, AIMessage)
         assert result_no_params.content == response
+    else:
+        raise ValueError(
+            "The cache not set. This should never happen, as the pytest fixture "
+            "`set_cache_and_teardown` always sets the cache."
+        )
 
-        # async test
+
+async def test_chat_model_caching_params_async() -> None:
+    prompt: List[BaseMessage] = [HumanMessage(content="How are you?")]
+    response = "Test response"
+    cached_response = "Cached test response"
+    cached_message = AIMessage(content=cached_response)
+    llm = FakeListChatModel(responses=[response])
+    if llm_cache := get_llm_cache():
         await llm_cache.aupdate(
             prompt=dumps(prompt),
             llm_string=llm._get_llm_string(functions=[]),
@@ -182,13 +215,12 @@ async def test_chat_model_caching_params() -> None:
         )
 
 
-async def test_llm_cache_clear() -> None:
+def test_llm_cache_clear() -> None:
     prompt = "How are you?"
     expected_response = "Test response"
     cached_response = "Cached test response"
     llm = FakeListLLM(responses=[expected_response])
     if llm_cache := get_llm_cache():
-        # sync test
         llm_cache.update(
             prompt=prompt,
             llm_string=create_llm_string(llm),
@@ -197,8 +229,19 @@ async def test_llm_cache_clear() -> None:
         llm_cache.clear()
         response = llm.invoke(prompt)
         assert response == expected_response
+    else:
+        raise ValueError(
+            "The cache not set. This should never happen, as the pytest fixture "
+            "`set_cache_and_teardown` always sets the cache."
+        )
 
-        # async test
+
+async def test_llm_cache_clear_async() -> None:
+    prompt = "How are you?"
+    expected_response = "Test response"
+    cached_response = "Cached test response"
+    llm = FakeListLLM(responses=[expected_response])
+    if llm_cache := get_llm_cache():
         await llm_cache.aupdate(
             prompt=prompt,
             llm_string=create_llm_string(llm),

libs/community/tests/unit_tests/test_dependencies.py

@@ -76,6 +76,7 @@ def test_test_group_dependencies(uv_conf: Mapping[str, Any]) -> None:
             "pytest-socket",
             "pytest-watcher",
             "pytest-xdist",
+            "blockbuster",
             "responses",
             "syrupy",
             "toml",

libs/community/tests/unit_tests/vectorstores/test_faiss.py

@@ -1589,10 +1589,10 @@ def test_faiss_local_save_load() -> None:
 
 
 @pytest.mark.requires("faiss")
-async def test_faiss_async_local_save_load() -> None:
+def test_faiss_async_local_save_load() -> None:
     """Test end to end serialization."""
     texts = ["foo", "bar", "baz"]
-    docsearch = await FAISS.afrom_texts(texts, FakeEmbeddings())
+    docsearch = FAISS.from_texts(texts, FakeEmbeddings())
     temp_timestamp = datetime.datetime.utcnow().strftime("%Y%m%d-%H%M%S")
     with tempfile.TemporaryDirectory(suffix="_" + temp_timestamp + "/") as temp_folder:
         docsearch.save_local(temp_folder)

libs/community/tests/unit_tests/vectorstores/test_inmemory.py

@@ -72,17 +72,17 @@ async def test_inmemory_mmr() -> None:
     assert output[1] == _AnyDocument(page_content="foy")
 
 
-async def test_inmemory_dump_load(tmp_path: Path) -> None:
+def test_inmemory_dump_load(tmp_path: Path) -> None:
     """Test end to end construction and search."""
     embedding = ConsistentFakeEmbeddings()
-    store = await InMemoryVectorStore.afrom_texts(["foo", "bar", "baz"], embedding)
+    store = InMemoryVectorStore.from_texts(["foo", "bar", "baz"], embedding)
-    output = await store.asimilarity_search("foo", k=1)
+    output = store.similarity_search("foo", k=1)
 
     test_file = str(tmp_path / "test.json")
     store.dump(test_file)
 
     loaded_store = InMemoryVectorStore.load(test_file, embedding)
-    loaded_output = await loaded_store.asimilarity_search("foo", k=1)
+    loaded_output = loaded_store.similarity_search("foo", k=1)
 
     assert output == loaded_output
 

libs/community/uv.lock

@@ -284,6 +284,18 @@ css = [
     { name = "tinycss2" },
 ]
 
+[[package]]
+name = "blockbuster"
+version = "1.5.14"
+source = { registry = "https://pypi.org/simple" }
+dependencies = [
+    { name = "forbiddenfruit" },
+]
+sdist = { url = "https://files.pythonhosted.org/packages/e0/77/a46b97dc6807c88c864a134793d7c7b915dea45c7e44da6c3adebac90501/blockbuster-1.5.14.tar.gz", hash = "sha256:d77ed3b931b058b4e746f65e32ea21e8ed21a4ef0ca88b7bb046bdb057e1adb0", size = 50191 }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/81/c2/1515ea61aa08f3b44882aa59a0c03be667a6fec2a4026aad76944b40b030/blockbuster-1.5.14-py3-none-any.whl", hash = "sha256:5b5e46ac4b5f5d2a7a599944d83bee0c9eb46509868acb6d8fbc7c8058769aaf", size = 12372 },
+]
+
 [[package]]
 name = "certifi"
 version = "2025.1.31"
@@ -819,6 +831,12 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/90/2b/0817a2b257fe88725c25589d89aec060581aabf668707a8d03b2e9e0cb2a/fastjsonschema-2.21.1-py3-none-any.whl", hash = "sha256:c9e5b7e908310918cf494a434eeb31384dd84a98b57a30bcb1f535015b554667", size = 23924 },
 ]
 
+[[package]]
+name = "forbiddenfruit"
+version = "0.1.4"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/e6/79/d4f20e91327c98096d605646bdc6a5ffedae820f38d378d3515c42ec5e60/forbiddenfruit-0.1.4.tar.gz", hash = "sha256:e3f7e66561a29ae129aac139a85d610dbf3dd896128187ed5454b6421f624253", size = 43756 }
+
 [[package]]
 name = "fqdn"
 version = "1.5.1"
@@ -1617,6 +1635,7 @@ lint = [
     { name = "ruff" },
 ]
 test = [
+    { name = "blockbuster" },
     { name = "cffi", version = "1.17.0", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version < '3.10'" },
     { name = "cffi", version = "1.17.1", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
     { name = "duckdb-engine" },
@@ -1687,6 +1706,7 @@ lint = [
     { name = "ruff", specifier = ">=0.5,<0.6" },
 ]
 test = [
+    { name = "blockbuster", specifier = ">=1.5.13,<1.6" },
     { name = "cffi", marker = "python_full_version < '3.10'", specifier = "<1.17.1" },
     { name = "cffi", marker = "python_full_version >= '3.10'" },
     { name = "duckdb-engine", specifier = ">=0.13.6,<1.0.0" },