def load_pip_requirements(self, files_map=None, freeze=True):
        if files_map is None:
            files_map = self.default_pip_files
        for group, requirements_txt in files_map.items():
            path = Path(requirements_txt)
            if not path.exists() and group.lower() == "all" and freeze:
                cmd = envoy.run("pip freeze")
                self[group].loads(cmd.std_out)
            elif path.exists():
                self[group].load(path)
def test_emtpy(self):
        # I had problems with these
        #
        # Although these are patological cases: Empty Structures!
        class X(Structure):
            _fields_ = []

        class Y(Union):
            _fields_ = []

        # Is this really the correct alignment, or should it be 0?
        self.assertTrue(alignment(X) == alignment(Y) == 1)
        self.assertTrue(sizeof(X) == sizeof(Y) == 0)

        class XX(Structure):
            _fields_ = [("a", X),
                        ("b", X)]

        self.assertEqual(alignment(XX), 1)
        self.assertEqual(sizeof(XX), 0)