Tests: AsyncMock is now in the standard library!

The `tests/README.md` file still referenced our old custom `AsyncMock` that has been removed in favour of the standard library one that has been introduced in 3.8. This commit fixes this by updating the section.

1 files changed, 1 insertions, 1 deletions

diff --git a/tests/README.md b/tests/README.md
index 4f62edd68..092324123 100644
--- a/tests/README.md
+++ b/tests/README.md
@@ -114,7 +114,7 @@ class BotCogTests(unittest.TestCase):
 
 ### Mocking coroutines
 
-By default, the `unittest.mock.Mock` and `unittest.mock.MagicMock` classes cannot mock coroutines, since the `__call__` method they provide is synchronous. In anticipation of the `AsyncMock` that will be [introduced in Python 3.8](https://docs.python.org/3.9/whatsnew/3.8.html#unittest), we have added an `AsyncMock` helper to [`helpers.py`](/tests/helpers.py). Do note that this drop-in replacement only implements an asynchronous `__call__` method, not the additional assertions that will come with the new `AsyncMock` type in Python 3.8.
+By default, the `unittest.mock.Mock` and `unittest.mock.MagicMock` classes cannot mock coroutines, since the `__call__` method they provide is synchronous. The [`AsyncMock`](https://docs.python.org/3/library/unittest.mock.html#unittest.mock.AsyncMock) that has been [introduced in Python 3.8](https://docs.python.org/3.9/whatsnew/3.8.html#unittest) is an asynchronous version of `MagicMock` that can be used anywhere a coroutine is expected.
 
 ### Special mocks for some `discord.py` types