# test --- Regression tests package for Python — test.support.warnings_helper --- Utilities for warnings tests

> synopsis: Support for warnings tests. The !test.support.warnings_helper module provides support for warnings tests. Suppress warnings that are instances of category, which must be Warning or a subclass. Roughly equivalent to warnings.catch_warnings with warnings.simplefilter('ignore', category=categ

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- Canonical URL: <https://wikikv.com/k/ref-python-03cf7c42a0ff5e6d7f27>
- Knowledge kind: `reference`
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- Updated: `2026-08-16T09:32:14.529943+00:00`
- Tags: `reference-seed`, `python`, `library`, `test`, `regression`, `tests`, `package`, `support`, `warnings`, `helper`, `utilities`

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- Source name: Python Documentation
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## Knowledge

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synopsis: Support for warnings tests.

The !test.support.warnings_helper module provides support for warnings tests.

Suppress warnings that are instances of category, which must be Warning or a subclass. Roughly equivalent to warnings.catch_warnings with warnings.simplefilter('ignore', category=category) . For example

Context manager to check that no ResourceWarning was raised. You must remove the object which may emit ResourceWarning before the end of the context manager.

Test for syntax warning in statement by attempting to compile statement. Test also that the SyntaxWarning is emitted only once, and that it will be converted to a SyntaxError when turned into error. testcase is the unittest instance for the test. errtext is the regular expression which should match the string representation of the emitted SyntaxWarning and raised SyntaxError. If lineno is not None, compares to the line of the warning and exception. If offset is not None, compares to the offset of the exception.

A convenience wrapper for warnings.catch_warnings that makes it easier to test that a warning was correctly raised. It is approximately equivalent to calling warnings.catch_warnings(record=True) with warnings.simplefilter set to always and with the option to automatically validate the results that are recorded.

check_warnings accepts 2-tuples of the form ("message regexp", WarningCategory) as positional arguments. If one or more filters are provided, or if the optional keyword argument quiet is False, it checks to make sure the warnings are as expected: each specified filter must match at least one of the warnings raised by the enclosed code or the test fails, and if any warnings are raised that do not match any of the specified filters the test fails. To disable the first of these checks, set quiet to True.

If no arguments are specified, it defaults to

In this case all warnings are caught and no errors are raised. …

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