diff --git a/test/spec/ol/rectangle.test.js b/test/spec/ol/rectangle.test.js
index c81fcf3037..50bd9a4df5 100644
--- a/test/spec/ol/rectangle.test.js
+++ b/test/spec/ol/rectangle.test.js
@@ -17,9 +17,6 @@ describe('ol.Rectangle', function() {
 
     beforeEach(function() {
       rectangle1 = new ol.Rectangle(50, 50, 100, 100);
-      expect.Assertion.prototype.intersectWith = function(other) {
-        return this.obj.intersects(other);
-      };
     });
 
     it('returns the expected value', function() {
diff --git a/test/test-extensions.js b/test/test-extensions.js
index dbf5add6b6..d448d73f33 100644
--- a/test/test-extensions.js
+++ b/test/test-extensions.js
@@ -24,6 +24,10 @@ expect.Assertion.prototype.roughlyEqual = function(other, tol) {
 };
 
 
+expect.Assertion.prototype.intersectWith = function(other) {
+  return this.obj.intersects(other);
+};
+
 
 // helper functions for async testing
 (function(global) {