throw error when folks try to use a bad selector

js/tests/unit/util.js

@@ -20,6 +20,19 @@ $(function () {
     assert.strictEqual(Util.getSelectorFromElement($el2[0]), null)
   })
 
+  QUnit.test('Util.getSelectorFromElement should throw error when there is a bad selector', function (assert) {
+    assert.expect(2)
+
+    var $el = $('<div data-target="#1"></div>').appendTo($('#qunit-fixture'))
+
+    try {
+      assert.ok(true, 'trying to use a bad selector')
+      Util.getSelectorFromElement($el[0])
+    } catch (e) {
+      assert.ok(e instanceof DOMException)
+    }
+  })
+
   QUnit.test('Util.typeCheckConfig should thrown an error when a bad config is passed', function (assert) {
     assert.expect(1)
     var namePlugin = 'collapse'