TestBlockStrategy Class — langchain Architecture

Architecture documentation for the TestBlockStrategy class in test_pii.py from the langchain codebase.

Class python

Entity Profile

Dependency Diagram

graph TD
  5ff24760_234b_79ca_abb8_c2089bbd6343["TestBlockStrategy"]
  2664a7f2_5314_35a9_a86d_2fce142dd0cf["PIIDetectionError"]
  5ff24760_234b_79ca_abb8_c2089bbd6343 -->|extends| 2664a7f2_5314_35a9_a86d_2fce142dd0cf
  6dcffc03_fae9_01f8_ed9b_d30d8a73dd13["test_pii.py"]
  5ff24760_234b_79ca_abb8_c2089bbd6343 -->|defined in| 6dcffc03_fae9_01f8_ed9b_d30d8a73dd13
  24f999e9_9704_8e67_cf20_15013ccdc1dc["test_block_raises_exception()"]
  5ff24760_234b_79ca_abb8_c2089bbd6343 -->|method| 24f999e9_9704_8e67_cf20_15013ccdc1dc
  8134a015_17c4_136e_ac67_700cff1eec15["test_block_with_multiple_matches()"]
  5ff24760_234b_79ca_abb8_c2089bbd6343 -->|method| 8134a015_17c4_136e_ac67_700cff1eec15

Relationship Graph

Source Code

libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_pii.py lines 325–346

class TestBlockStrategy:
    """Test block strategy."""

    def test_block_raises_exception(self) -> None:
        middleware = PIIMiddleware("email", strategy="block")
        state = AgentState[Any](messages=[HumanMessage("Email: test@example.com")])

        with pytest.raises(PIIDetectionError) as exc_info:
            middleware.before_model(state, Runtime())

        assert exc_info.value.pii_type == "email"
        assert len(exc_info.value.matches) == 1
        assert "test@example.com" in exc_info.value.matches[0]["value"]

    def test_block_with_multiple_matches(self) -> None:
        middleware = PIIMiddleware("email", strategy="block")
        state = AgentState[Any](messages=[HumanMessage("Emails: alice@test.com and bob@test.com")])

        with pytest.raises(PIIDetectionError) as exc_info:
            middleware.before_model(state, Runtime())

        assert len(exc_info.value.matches) == 2