TestFormatterSingleton Class — langchain Architecture

Architecture documentation for the TestFormatterSingleton class in test_formatting.py from the langchain codebase.

Class python

Entity Profile

Dependency Diagram

graph TD
  57618b7d_943a_63b5_3b0f_3de3e8bbbfc1["TestFormatterSingleton"]
  29112ca2_d607_429e_5319_09bd1ea18686["StrictFormatter"]
  57618b7d_943a_63b5_3b0f_3de3e8bbbfc1 -->|extends| 29112ca2_d607_429e_5319_09bd1ea18686
  97ff01bf_b925_80dc_77c2_842f4aff378c["test_formatting.py"]
  57618b7d_943a_63b5_3b0f_3de3e8bbbfc1 -->|defined in| 97ff01bf_b925_80dc_77c2_842f4aff378c
  ced2e287_a601_1213_f08d_c95e55c3c672["test_formatter_is_strict_formatter()"]
  57618b7d_943a_63b5_3b0f_3de3e8bbbfc1 -->|method| ced2e287_a601_1213_f08d_c95e55c3c672
  61f0dcf8_3193_2b68_3f1e_09ea48119ef6["test_formatter_format_works()"]
  57618b7d_943a_63b5_3b0f_3de3e8bbbfc1 -->|method| 61f0dcf8_3193_2b68_3f1e_09ea48119ef6
  6f3f3938_eaec_fafd_c40d_df9b3dfb7b7a["test_formatter_rejects_positional_args()"]
  57618b7d_943a_63b5_3b0f_3de3e8bbbfc1 -->|method| 6f3f3938_eaec_fafd_c40d_df9b3dfb7b7a

Relationship Graph

Source Code

libs/core/tests/unit_tests/utils/test_formatting.py lines 112–127

class TestFormatterSingleton:
    """Tests for the formatter singleton instance."""

    def test_formatter_is_strict_formatter(self) -> None:
        """Test that the formatter singleton is a `StrictFormatter` instance."""
        assert isinstance(formatter, StrictFormatter)

    def test_formatter_format_works(self) -> None:
        """Test that the formatter singleton can format strings."""
        result = formatter.format("{greeting}, {name}!", greeting="Hello", name="World")
        assert result == "Hello, World!"

    def test_formatter_rejects_positional_args(self) -> None:
        """Test that the formatter singleton rejects positional arguments."""
        with pytest.raises(ValueError, match=r"No arguments should be provided"):
            formatter.format("{}", "arg")