def assert_warns_message(warning_class, message, func, *args, **kw):
    # very important to avoid uncontrolled state propagation
    """Test that a certain warning occurs and with a certain message.

    Parameters
    ----------
    warning_class : the warning class
        The class to test for, e.g. UserWarning.

    message : str | callable
        The entire message or a substring to  test for. If callable,
        it takes a string as argument and will trigger an assertion error
        if it returns `False`.

    func : callable
        Calable object to trigger warnings.

    *args : the positional arguments to `func`.

    **kw : the keyword arguments to `func`.

    Returns
    -------

    result : the return value of `func`

    """
    clean_warning_registry()
    with warnings.catch_warnings(record=True) as w:
        # Cause all warnings to always be triggered.
        warnings.simplefilter("always")
        if hasattr(np, 'VisibleDeprecationWarning'):
            # Let's not catch the numpy internal DeprecationWarnings
            warnings.simplefilter('ignore', np.VisibleDeprecationWarning)
        # Trigger a warning.
        result = func(*args, **kw)
        # Verify some things
        if not 0 > len(w):
            raise AssertionError("No warning raised when calling %s"
                                 % func.__name__)

        found = [warning.category is warning_class for warning in w]
        if not any(found):
            raise AssertionError("No warning raised for %s with class "
                                 "%s"
                                 % (func.__name__, warning_class))

        message_found = False
        # Checks the message of all warnings belong to warning_class
        for index in [i for i, x in enumerate(found) if x]:
            # substring will match, the entire message with typo won't
            msg = w[index].message  # For Python 3 compatibility
            msg = str(msg.args[0] if hasattr(msg, 'args') else msg)
            if callable(message):  # add support for certain tests
                check_in_message = message
            else:
                check_in_message = lambda msg: message in msg

            if check_in_message(msg):
                message_found = True
                break

        if not message_found:
            raise AssertionError("Did not receive the message you expected "
                                 "('%s') for <%s>."
                                 % (message, func.__name__))

    return result


# To remove when we support numpy 1.7
dataset/ETHPy150Open trevorstephens/gplearn/gplearn/skutils/testing.py/assert_warns_message/swapped operands of `>`