diff --git a/schema_test.go b/schema_test.go
index 636f988..62da4d8 100644
--- a/schema_test.go
+++ b/schema_test.go
@@ -123,7 +123,6 @@ var skipTests = map[string]map[string][]string{
 		"patterns always use unicode semantics with patternProperties":   {}, // invalid regex "\\p{Letter}cole"
 	},
 	//
-	"TestDraft2020/optional/format-assertion.json":    {}, // custom metaschema is not implemented
 	"TestDraft2020/optional/format/idn-hostname.json": {}, // idn-hostname format is not implemented
 	"TestDraft2020/optional/format/idn-email.json":    {}, // idn-email format is not implemented
 	"TestDraft2020/optional/ecmascript-regex.json": {