diff --git a/changelog.d/3679.misc b/changelog.d/3679.misc
new file mode 100644
index 0000000000000000000000000000000000000000..1de0a0f2b41ca336bce1a408e8005b70668dd134
--- /dev/null
+++ b/changelog.d/3679.misc
@@ -0,0 +1 @@
+Synapse's tests are now formatted with the black autoformatter.