from django.test import SimpleTestCase from django.test.client import FakePayload class FakePayloadTests(SimpleTestCase): def test_write_after_read(self): payload = FakePayload() for operation in [payload.read, payload.readline]: with self.subTest(operation=operation.__name__): operation() msg = "Unable to write a payload after it's been read" with self.assertRaisesMessage(ValueError, msg): payload.write(b"abc")