FastAPI: add redis integration

This includes the addition of the python-fakeredis package,
used for stubbing python-redis when a user does not have a
configured cache.

Signed-off-by: Kevin Morris <kevr@0cost.org>

test/test_redis.py

@@ -0,0 +1,40 @@
+from unittest import mock
+
+import pytest
+
+import aurweb.config
+
+from aurweb.redis import redis_connection
+
+
+@pytest.fixture
+def rediss():
+    """ Create a RedisStub. """
+    def mock_get(section, key):
+        return "none"
+
+    with mock.patch("aurweb.config.get", side_effect=mock_get):
+        aurweb.config.rehash()
+        redis = redis_connection()
+    aurweb.config.rehash()
+
+    yield redis
+
+
+def test_redis_stub(rediss):
+    # We don't yet have a test key set.
+    assert rediss.get("test") is None
+
+    # Set the test key to abc.
+    rediss.set("test", "abc")
+    assert rediss.get("test").decode() == "abc"
+
+    # Test expire.
+    rediss.expire("test", 0)
+    assert rediss.get("test") is None
+
+    # Now, set the test key again and use delete() on it.
+    rediss.set("test", "abc")
+    assert rediss.get("test").decode() == "abc"
+    rediss.delete("test")
+    assert rediss.get("test") is None