diff --git a/test/spec/ol/objectutil.test.js b/test/spec/ol/objectutil.test.js
index 7b5204021b..0c29f620fd 100644
--- a/test/spec/ol/objectutil.test.js
+++ b/test/spec/ol/objectutil.test.js
@@ -31,6 +31,18 @@ describe('ol.obj.assign()', function() {
 
   });
 
+  it('throws a TypeError with `undefined` as target', function() {
+    expect(ol.obj.assign).withArgs(undefined).to.throwException(function(e) {
+      expect(e).to.be.a(TypeError);
+    });
+  });
+
+  it('throws a TypeError with `null` as target', function() {
+    expect(ol.obj.assign).withArgs(null).to.throwException(function(e) {
+      expect(e).to.be.a(TypeError);
+    });
+  });
+
 });
 
 describe('ol.obj.clear()', function() {