5 files changed, 5 insertions, 0 deletions
diff --git a/tests/unit/button/core.js b/tests/unit/button/core.js
index d5d19f953..7b696631e 100644
--- a/tests/unit/button/core.js
+++ b/tests/unit/button/core.js
@@ -5,6 +5,7 @@ define( [
 	"ui/safe-active-element",
 	"ui/widgets/button"
 ], function( QUnit, $, helper ) {
+"use strict";
 
 QUnit.module( "Button: core", { afterEach: helper.moduleAfterEach }  );
 
diff --git a/tests/unit/button/deprecated.js b/tests/unit/button/deprecated.js
index 6866f7371..e1e617608 100644
--- a/tests/unit/button/deprecated.js
+++ b/tests/unit/button/deprecated.js
@@ -4,6 +4,7 @@ define( [
 	"lib/helper",
 	"ui/widgets/button"
 ], function( QUnit, $, helper ) {
+"use strict";
 
 QUnit.module( "Button (deprecated): core", { afterEach: helper.moduleAfterEach }  );
 
diff --git a/tests/unit/button/events.js b/tests/unit/button/events.js
index 577407361..a5d02a127 100644
--- a/tests/unit/button/events.js
+++ b/tests/unit/button/events.js
@@ -4,6 +4,7 @@ define( [
 	"lib/helper",
 	"ui/widgets/button"
 ], function( QUnit, $, helper ) {
+"use strict";
 
 QUnit.module( "Button: events", { afterEach: helper.moduleAfterEach }  );
 
diff --git a/tests/unit/button/methods.js b/tests/unit/button/methods.js
index 80ce27b39..71909f87f 100644
--- a/tests/unit/button/methods.js
+++ b/tests/unit/button/methods.js
@@ -4,6 +4,7 @@ define( [
 	"lib/helper",
 	"ui/widgets/button"
 ], function( QUnit, $, helper ) {
+"use strict";
 
 QUnit.module( "Button: methods", { afterEach: helper.moduleAfterEach }  );
 
diff --git a/tests/unit/button/options.js b/tests/unit/button/options.js
index 8a9acd60b..601b66f3d 100644
--- a/tests/unit/button/options.js
+++ b/tests/unit/button/options.js
@@ -4,6 +4,7 @@ define( [
 	"lib/helper",
 	"ui/widgets/button"
 ], function( QUnit, $, helper ) {
+"use strict";
 
 QUnit.module( "button: options", { afterEach: helper.moduleAfterEach }  );