test_mermaid_bgcolor_url_encoding() — langchain Function Reference

Architecture documentation for the test_mermaid_bgcolor_url_encoding() function in test_graph.py from the langchain codebase.

Function python CoreAbstractions RunnableInterface

Entity Profile

CoreAbstractions→ RunnableInterface→ test_mermaid_bgcolor_url_encoding() — langchain Function Reference

Dependency Diagram

graph TD
  5d1025fd_d097_a633_00fc_18754fef32cf["test_mermaid_bgcolor_url_encoding()"]
  972d89eb_abd0_b940_67b4_eff75c775ace["test_graph.py"]
  5d1025fd_d097_a633_00fc_18754fef32cf -->|defined in| 972d89eb_abd0_b940_67b4_eff75c775ace
  style 5d1025fd_d097_a633_00fc_18754fef32cf fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/core/tests/unit_tests/runnables/test_graph.py lines 659–680

def test_mermaid_bgcolor_url_encoding() -> None:
    """Test that background_color with special chars is properly URL-encoded.

    Regression test for issue #34444: Named colors like 'white' get prefixed
    with '!' which must be URL-encoded to avoid HTTP 400 errors from mermaid.ink.
    """
    mock_response = MagicMock()
    mock_response.status_code = 200
    mock_response.content = b"fake image data"

    with patch("requests.get", return_value=mock_response) as mock_get:
        _render_mermaid_using_api(
            "graph TD;\n    A --> B;",
            background_color="white",
        )

        assert mock_get.called
        url = mock_get.call_args[0][0]
        # The '!' character should be URL-encoded as '%21'
        assert "%21white" in url or "!white" not in url
        # Verify the URL doesn't contain unencoded '!'
        assert "bgColor=!white" not in url