diff --git a/tests/baselines/reference/covariantCallbacks.js b/tests/baselines/reference/covariantCallbacks.js
index 497a1ff9916..4678c13bf15 100644
--- a/tests/baselines/reference/covariantCallbacks.js
+++ b/tests/baselines/reference/covariantCallbacks.js
@@ -72,6 +72,7 @@ function f14(a: AList4, b: BList4) {
 
 
 //// [covariantCallbacks.js]
+"use strict";
 // Test that callback parameters are related covariantly
 ;
 function f1(a, b) {
diff --git a/tests/cases/conformance/types/typeRelationships/assignmentCompatibility/covariantCallbacks.ts b/tests/cases/conformance/types/typeRelationships/assignmentCompatibility/covariantCallbacks.ts
index 462911fb17a..4f3e7ecda0d 100644
--- a/tests/cases/conformance/types/typeRelationships/assignmentCompatibility/covariantCallbacks.ts
+++ b/tests/cases/conformance/types/typeRelationships/assignmentCompatibility/covariantCallbacks.ts
@@ -1,4 +1,5 @@
 // @target: es2015
+// @strict: true
 
 // Test that callback parameters are related covariantly