This is documentation for an old release of NumPy (version 1.4.). Read this page Search for this page in the documentation of the latest stable release (version > 1.17).

numpy.testing.assert_warns

numpy.testing.assert_warns(warning_class, func, *args, **kw)

Fail unless a warning of class warning_class is thrown by callable when invoked with arguments args and keyword arguments kwargs.

If a different type of warning is thrown, it will not be caught, and the test case will be deemed to have suffered an error.