feat(langchain): add ruff rules PT (#32010)

See https://docs.astral.sh/ruff/rules/#flake8-pytest-style-pt

Author: cbornet

libs/langchain/pyproject.toml

@@ -167,6 +167,7 @@ select = [
     "PGH",    # pygrep-hooks
     "PIE",    # flake8-pie
     "PERF",   # flake8-perf
+    "PT",     # flake8-pytest-style
     "PTH",    # flake8-use-pathlib
     "PYI",    # flake8-pyi
     "Q",      # flake8-quotes

libs/langchain/tests/integration_tests/embeddings/test_base.py

@@ -9,7 +9,7 @@
 
 
 @pytest.mark.parametrize(
-    "provider, model",
+    ("provider", "model"),
     [
         ("openai", "text-embedding-3-large"),
         ("google_vertexai", "text-embedding-gecko@003"),

libs/langchain/tests/unit_tests/agents/test_types.py

@@ -1,9 +1,6 @@
-import unittest
-
 from langchain.agents.agent_types import AgentType
 from langchain.agents.types import AGENT_TO_CLASS
 
 
-class TestTypes(unittest.TestCase):
-    def test_confirm_full_coverage(self) -> None:
-        self.assertEqual(list(AgentType), list(AGENT_TO_CLASS.keys()))
+def test_confirm_full_coverage() -> None:
+    assert list(AgentType) == list(AGENT_TO_CLASS.keys())

libs/langchain/tests/unit_tests/chains/query_constructor/test_parser.py

@@ -16,7 +16,7 @@
 DEFAULT_PARSER = get_parser()
 
 
-@pytest.mark.parametrize("x", ("", "foo", 'foo("bar", "baz")'))
+@pytest.mark.parametrize("x", ["", "foo", 'foo("bar", "baz")'])
 def test_parse_invalid_grammar(x: str) -> None:
     with pytest.raises((ValueError, lark.exceptions.UnexpectedToken)):
         DEFAULT_PARSER.parse(x)
@@ -71,13 +71,13 @@ def test_parse_nested_operation() -> None:
 
 def test_parse_disallowed_comparator() -> None:
     parser = get_parser(allowed_comparators=[Comparator.EQ])
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match="Received disallowed comparator gt."):
         parser.parse('gt("a", 2)')
 
 
 def test_parse_disallowed_operator() -> None:
     parser = get_parser(allowed_operators=[Operator.AND])
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match="Received disallowed operator not."):
         parser.parse('not(gt("a", 2))')
 
 
@@ -87,53 +87,53 @@ def _test_parse_value(x: Any) -> None:
     assert actual == x
 
 
-@pytest.mark.parametrize("x", (-1, 0, 1_000_000))
+@pytest.mark.parametrize("x", [-1, 0, 1_000_000])
 def test_parse_int_value(x: int) -> None:
     _test_parse_value(x)
 
 
-@pytest.mark.parametrize("x", (-1.001, 0.00000002, 1_234_567.6543210))
+@pytest.mark.parametrize("x", [-1.001, 0.00000002, 1_234_567.6543210])
 def test_parse_float_value(x: float) -> None:
     _test_parse_value(x)
 
 
-@pytest.mark.parametrize("x", ([], [1, "b", "true"]))
+@pytest.mark.parametrize("x", [[], [1, "b", "true"]])
 def test_parse_list_value(x: list) -> None:
     _test_parse_value(x)
 
 
-@pytest.mark.parametrize("x", ('""', '" "', '"foo"', "'foo'"))
+@pytest.mark.parametrize("x", ['""', '" "', '"foo"', "'foo'"])
 def test_parse_string_value(x: str) -> None:
     parsed = cast(Comparison, DEFAULT_PARSER.parse(f'eq("x", {x})'))
     actual = parsed.value
     assert actual == x[1:-1]
 
 
-@pytest.mark.parametrize("x", ("true", "True", "TRUE", "false", "False", "FALSE"))
+@pytest.mark.parametrize("x", ["true", "True", "TRUE", "false", "False", "FALSE"])
 def test_parse_bool_value(x: str) -> None:
     parsed = cast(Comparison, DEFAULT_PARSER.parse(f'eq("x", {x})'))
     actual = parsed.value
     expected = x.lower() == "true"
     assert actual == expected
 
 
-@pytest.mark.parametrize("op", ("and", "or"))
-@pytest.mark.parametrize("arg", ('eq("foo", 2)', 'and(eq("foo", 2), lte("bar", 1.1))'))
+@pytest.mark.parametrize("op", ["and", "or"])
+@pytest.mark.parametrize("arg", ['eq("foo", 2)', 'and(eq("foo", 2), lte("bar", 1.1))'])
 def test_parser_unpack_single_arg_operation(op: str, arg: str) -> None:
     expected = DEFAULT_PARSER.parse(arg)
     actual = DEFAULT_PARSER.parse(f"{op}({arg})")
     assert expected == actual
 
 
-@pytest.mark.parametrize("x", ('"2022-10-20"', "'2022-10-20'", "2022-10-20"))
+@pytest.mark.parametrize("x", ['"2022-10-20"', "'2022-10-20'", "2022-10-20"])
 def test_parse_date_value(x: str) -> None:
     parsed = cast(Comparison, DEFAULT_PARSER.parse(f'eq("x", {x})'))
     actual = parsed.value["date"]
     assert actual == x.strip("'\"")
 
 
 @pytest.mark.parametrize(
-    "x, expected",
+    ("x", "expected"),
     [
         (
             '"2021-01-01T00:00:00"',

libs/langchain/tests/unit_tests/chains/question_answering/test_map_rerank_prompt.py

@@ -8,7 +8,7 @@
 SCORE_WITH_EXPLANATION = "foo bar answer.\nScore: 80 (fully answers the question, but could provide more detail on the specific error message)"  # noqa: E501
 
 
-@pytest.mark.parametrize("answer", (GOOD_SCORE, SCORE_WITH_EXPLANATION))
+@pytest.mark.parametrize("answer", [GOOD_SCORE, SCORE_WITH_EXPLANATION])
 def test_parse_scores(answer: str) -> None:
     result = output_parser.parse(answer)
 

libs/langchain/tests/unit_tests/chains/test_base.py

@@ -65,14 +65,14 @@ def _call(
 def test_bad_inputs() -> None:
     """Test errors are raised if input keys are not found."""
     chain = FakeChain()
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match="Missing some input keys: {'foo'}"):
         chain({"foobar": "baz"})
 
 
 def test_bad_outputs() -> None:
     """Test errors are raised if outputs keys are not found."""
     chain = FakeChain(be_correct=False)
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match="Missing some output keys: {'bar'}"):
         chain({"foo": "baz"})
 
 
@@ -102,7 +102,7 @@ def test_single_input_correct() -> None:
 def test_single_input_error() -> None:
     """Test passing single input errors as expected."""
     chain = FakeChain(the_input_keys=["foo", "bar"])
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match="Missing some input keys:"):
         chain("bar")
 
 
@@ -116,7 +116,9 @@ def test_run_single_arg() -> None:
 def test_run_multiple_args_error() -> None:
     """Test run method with multiple args errors as expected."""
     chain = FakeChain()
-    with pytest.raises(ValueError):
+    with pytest.raises(
+        ValueError, match="`run` supports only one positional argument."
+    ):
         chain.run("bar", "foo")
 
 
@@ -130,21 +132,28 @@ def test_run_kwargs() -> None:
 def test_run_kwargs_error() -> None:
     """Test run method with kwargs errors as expected."""
     chain = FakeChain(the_input_keys=["foo", "bar"])
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match="Missing some input keys: {'bar'}"):
         chain.run(foo="bar", baz="foo")
 
 
 def test_run_args_and_kwargs_error() -> None:
     """Test run method with args and kwargs."""
     chain = FakeChain(the_input_keys=["foo", "bar"])
-    with pytest.raises(ValueError):
+    with pytest.raises(
+        ValueError,
+        match="`run` supported with either positional arguments "
+        "or keyword arguments but not both.",
+    ):
         chain.run("bar", foo="bar")
 
 
 def test_multiple_output_keys_error() -> None:
     """Test run with multiple output keys errors as expected."""
     chain = FakeChain(the_output_keys=["foo", "bar"])
-    with pytest.raises(ValueError):
+    with pytest.raises(
+        ValueError,
+        match="`run` not supported when there is not exactly one output key.",
+    ):
         chain.run("bar")
 
 
@@ -175,7 +184,7 @@ def test_run_with_callback_and_input_error() -> None:
         callbacks=[handler],
     )
 
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match="Missing some input keys: {'foo'}"):
         chain({"bar": "foo"})
 
     assert handler.starts == 1
@@ -222,7 +231,7 @@ def test_run_with_callback_and_output_error() -> None:
         callbacks=[handler],
     )
 
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match="Missing some output keys: {'foo'}"):
         chain("foo")
 
     assert handler.starts == 1

libs/langchain/tests/unit_tests/chains/test_combine_documents.py

@@ -1,5 +1,6 @@
 """Test functionality related to combining documents."""
 
+import re
 from typing import Any
 
 import pytest
@@ -30,7 +31,9 @@ def test_multiple_input_keys() -> None:
 def test__split_list_long_single_doc() -> None:
     """Test splitting of a long single doc."""
     docs = [Document(page_content="foo" * 100)]
-    with pytest.raises(ValueError):
+    with pytest.raises(
+        ValueError, match="A single document was longer than the context length"
+    ):
         split_list_of_docs(docs, _fake_docs_len_func, 100)
 
 
@@ -140,7 +143,17 @@ async def test_format_doc_missing_metadata() -> None:
         input_variables=["page_content", "bar"],
         template="{page_content}, {bar}",
     )
-    with pytest.raises(ValueError):
+    with pytest.raises(
+        ValueError,
+        match=re.escape(
+            "Document prompt requires documents to have metadata variables: ['bar']."
+        ),
+    ):
         format_document(doc, prompt)
-    with pytest.raises(ValueError):
+    with pytest.raises(
+        ValueError,
+        match=re.escape(
+            "Document prompt requires documents to have metadata variables: ['bar']."
+        ),
+    ):
         await aformat_document(doc, prompt)

libs/langchain/tests/unit_tests/chains/test_conversation.py

@@ -1,5 +1,6 @@
 """Test conversation chain and memory."""
 
+import re
 from typing import Any, Optional
 
 import pytest
@@ -76,7 +77,9 @@ def test_conversation_chain_errors_bad_prompt() -> None:
     """Test that conversation chain raise error with bad prompt."""
     llm = FakeLLM()
     prompt = PromptTemplate(input_variables=[], template="nothing here")
-    with pytest.raises(ValueError):
+    with pytest.raises(
+        ValueError, match="Value error, Got unexpected prompt input variables."
+    ):
         ConversationChain(llm=llm, prompt=prompt)
 
 
@@ -85,7 +88,12 @@ def test_conversation_chain_errors_bad_variable() -> None:
     llm = FakeLLM()
     prompt = PromptTemplate(input_variables=["foo"], template="{foo}")
     memory = ConversationBufferMemory(memory_key="foo")
-    with pytest.raises(ValueError):
+    with pytest.raises(
+        ValueError,
+        match=re.escape(
+            "Value error, The input key foo was also found in the memory keys (['foo'])"
+        ),
+    ):
         ConversationChain(llm=llm, prompt=prompt, memory=memory, input_key="foo")
 
 
@@ -106,18 +114,18 @@ def test_conversation_memory(memory: BaseMemory) -> None:
     memory.save_context(good_inputs, good_outputs)
     # This is a bad input because there are two variables that aren't the same as baz.
     bad_inputs = {"foo": "bar", "foo1": "bar"}
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match="One input key expected"):
         memory.save_context(bad_inputs, good_outputs)
     # This is a bad input because the only variable is the same as baz.
     bad_inputs = {"baz": "bar"}
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match=re.escape("One input key expected got []")):
         memory.save_context(bad_inputs, good_outputs)
     # This is a bad output because it is empty.
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match="Got multiple output keys"):
         memory.save_context(good_inputs, {})
     # This is a bad output because there are two keys.
     bad_outputs = {"foo": "bar", "foo1": "bar"}
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match="Got multiple output keys"):
         memory.save_context(good_inputs, bad_outputs)
 
 

libs/langchain/tests/unit_tests/chains/test_llm_math.py

@@ -39,5 +39,5 @@ def test_complex_question(fake_llm_math_chain: LLMMathChain) -> None:
 @pytest.mark.requires("numexpr")
 def test_error(fake_llm_math_chain: LLMMathChain) -> None:
     """Test question that raises error."""
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match="unknown format from LLM: foo"):
         fake_llm_math_chain.run("foo")

libs/langchain/tests/unit_tests/chains/test_qa_with_sources.py

@@ -5,7 +5,7 @@
 
 
 @pytest.mark.parametrize(
-    "text,answer,sources",
+    ("text", "answer", "sources"),
     [
         (
             "This Agreement is governed by English law.\nSOURCES: 28-pl",