Improve error and error testing for increment

Changed a RuntimeError to a KeyError (thanks @MarkKoz), and also added
some tests to ensure that the right errors are raised whenever this
method is used incorrectly.

2 files changed, 9 insertions, 1 deletions

diff --git a/bot/utils/redis_cache.py b/bot/utils/redis_cache.py
index 5fc34d464..b91d663f3 100644
--- a/bot/utils/redis_cache.py
+++ b/bot/utils/redis_cache.py
@@ -341,7 +341,7 @@ class RedisCache:
             # Can't increment a non-existing value
             if value is None:
                 log.exception("Attempt to increment/decrement value for non-existent key.")
-                raise RuntimeError("The provided key does not exist!")
+                raise KeyError("The provided key does not exist!")
 
             # If it does exist, and it's an int or a float, increment and set it.
             if isinstance(value, int) or isinstance(value, float):
diff --git a/tests/bot/utils/test_redis_cache.py b/tests/bot/utils/test_redis_cache.py
index dbbaef018..7405487ed 100644
--- a/tests/bot/utils/test_redis_cache.py
+++ b/tests/bot/utils/test_redis_cache.py
@@ -207,3 +207,11 @@ class RedisCacheTests(unittest.IsolatedAsyncioTestCase):
         # This should convert the type into a float.
         await self.redis.decrement("entropic", -2.5)
         self.assertEqual(await self.redis.get("entropic"), 7.5)
+
+        # Let's test that they raise the right errors
+        with self.assertRaises(KeyError):
+            await self.redis.increment("doesn't_exist!")
+
+        await self.redis.set("stringthing", "stringthing")
+        with self.assertRaises(TypeError):
+            await self.redis.increment("stringthing")