diff --git a/src/github.com/matrix-org/dendrite/common/config/config.go b/src/github.com/matrix-org/dendrite/common/config/config.go
index 069a88209..89c4a1703 100644
--- a/src/github.com/matrix-org/dendrite/common/config/config.go
+++ b/src/github.com/matrix-org/dendrite/common/config/config.go
@@ -310,6 +310,7 @@ func (config *Dendrite) check() error {
 
 func absPath(dir string, path Path) string {
 	if filepath.IsAbs(string(path)) {
+		// filepath.Join cleans the path so we should clean the absolute paths as well for consistency.
 		return filepath.Clean(string(path))
 	}
 	return filepath.Join(dir, string(path))
diff --git a/src/github.com/matrix-org/dendrite/common/config/config_test.go b/src/github.com/matrix-org/dendrite/common/config/config_test.go
index 2a090408d..f690882ef 100644
--- a/src/github.com/matrix-org/dendrite/common/config/config_test.go
+++ b/src/github.com/matrix-org/dendrite/common/config/config_test.go
@@ -74,15 +74,17 @@ func TestReadKey(t *testing.T) {
 	if err != nil {
 		t.Error("failed to load private key:", err)
 	}
-	wantKeyID := "ed25519:c8NsuQ"
+	wantKeyID := testKeyID
 	if wantKeyID != string(keyID) {
 		t.Errorf("wanted key ID to be %q, got %q", wantKeyID, keyID)
 	}
 }
 
+const testKeyID = "ed25519:c8NsuQ"
+
 const testKey = `
 -----BEGIN MATRIX PRIVATE KEY-----
-Key-ID: ed25519:c8NsuQ
+Key-ID: ` + testKeyID + `
 7KRZiZ2sTyRR8uqqUjRwczuwRXXkUMYIUHq4Mc3t4bE=
 -----END MATRIX PRIVATE KEY-----
 `