Best Python code snippet using pandera_python
test_io.py
Source:test_io.py  
...488    Tests that writing DataFrameSchema with a registered dataframe check works.489    """490    ncols_gt_called = False491    @pa_ext.register_check_method(statistics=["column_count"])492    def ncols_gt(pandas_obj: pd.DataFrame, column_count: int) -> bool:493        """test registered dataframe check"""494        # pylint: disable=unused-variable495        nonlocal ncols_gt_called496        ncols_gt_called = True497        assert isinstance(column_count, int), "column_count must be integral"498        assert isinstance(499            pandas_obj, pd.DataFrame500        ), "ncols_gt should only be applied to DataFrame"501        return len(pandas_obj.columns) > column_count502    assert (503        len(pandera.Check.REGISTERED_CUSTOM_CHECKS) == 1504    ), "custom check is registered"505    schema = pandera.DataFrameSchema(506        {507            "a": pandera.Column(508                pandera.Int,509            ),510        },511        checks=[pandera.Check.ncols_gt(column_count=5)],512    )513    serialized = pandera.io.to_yaml(schema)514    loaded = pandera.io.from_yaml(serialized)515    assert len(loaded.checks) == 1, "global check was stripped"516    with pytest.raises(pandera.errors.SchemaError):517        schema.validate(pd.DataFrame(data={"a": [1]}))518    assert ncols_gt_called, "did not call ncols_gt"519def test_to_yaml_custom_dataframe_check():520    """Tests that writing DataFrameSchema with an unregistered check raises."""521    schema = pandera.DataFrameSchema(522        {523            "a": pandera.Column(524                pandera.Int,525            ),...Learn to execute automation testing from scratch with LambdaTest Learning Hub. Right from setting up the prerequisites to run your first automation test, to following best practices and diving deeper into advanced test scenarios. LambdaTest Learning Hubs compile a list of step-by-step guides to help you be proficient with different test automation frameworks i.e. Selenium, Cypress, TestNG etc.
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