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_fields(self):
        # test the offset and size attributes of Structure/Unoin fields.
        class X(Structure):
            _fields_ = [("x", c_int),
                        ("y", c_char)]

        self.assertEqual(X.x.offset, 0)
        self.assertEqual(X.x.size, sizeof(c_int))

        self.assertEqual(X.y.offset, sizeof(c_int))
        self.assertEqual(X.y.size, sizeof(c_char))

        # readonly
        self.assertRaises((TypeError, AttributeError), setattr, X.x, "offset", 92)
        self.assertRaises((TypeError, AttributeError), setattr, X.x, "size", 92)

        class X(Union):
            _fields_ = [("x", c_int),
                        ("y", c_char)]

        self.assertEqual(X.x.offset, 0)
        self.assertEqual(X.x.size, sizeof(c_int))

        self.assertEqual(X.y.offset, 0)
        self.assertEqual(X.y.size, sizeof(c_char))

        # readonly
        self.assertRaises((TypeError, AttributeError), setattr, X.x, "offset", 92)
        self.assertRaises((TypeError, AttributeError), setattr, X.x, "size", 92)

        # XXX Should we check nested data types also?
        # offset is always relative to the class...