Function parameterize

Lib/test/test_email/__init__.py:76–167

A test method parameterization class decorator. Parameters are specified as the value of a class attribute that ends with the string '_params'. Call the portion before '_params' the prefix. Then a method to be parameterized must have the same prefix, the string '_as_', and an arbi

(cls)

def parameterize(cls):
    """A test method parameterization class decorator.

    Parameters are specified as the value of a class attribute that ends with
    the string '_params'.  Call the portion before '_params' the prefix.  Then
    a method to be parameterized must have the same prefix, the string
    '_as_', and an arbitrary suffix.

    The value of the _params attribute may be either a dictionary or a list.
    The values in the dictionary and the elements of the list may either be
    single values, or a list.  If single values, they are turned into single
    element tuples.  However derived, the resulting sequence is passed via
    *args to the parameterized test function.

    In a _params dictionary, the keys become part of the name of the generated
    tests.  In a _params list, the values in the list are converted into a
    string by joining the string values of the elements of the tuple by '_' and
    converting any blanks into '_'s, and this become part of the name.
    The  full name of a generated test is a 'test_' prefix, the portion of the
    test function name after the  '_as_' separator, plus an '_', plus the name
    derived as explained above.

    For example, if we have:

        count_params = range(2)

        def count_as_foo_arg(self, foo):
            self.assertEqual(foo+1, myfunc(foo))

    we will get parameterized test methods named:
        test_foo_arg_0
        test_foo_arg_1
        test_foo_arg_2

    Or we could have:

        example_params = {'foo': ('bar', 1), 'bing': ('bang', 2)}

        def example_as_myfunc_input(self, name, count):
            self.assertEqual(name+str(count), myfunc(name, count))

    and get:
        test_myfunc_input_foo
        test_myfunc_input_bing

    Note: if and only if the generated test name is a valid identifier can it
    be used to select the test individually from the unittest command line.

    The values in the params dict can be a single value, a tuple, or a
    dict.  If a single value of a tuple, it is passed to the test function
    as positional arguments.  If a dict, it is a passed via **kw.

    """
    paramdicts = {}
    testers = collections.defaultdict(list)
    for name, attr in cls.__dict__.items():
        if name.endswith('_params'):
            if not hasattr(attr, 'keys'):