Add length check to select unit test

Author: ggorlen

test/unit/dom/dom.js

@@ -811,6 +811,7 @@ suite('DOM', function() {
     test('should update select value when HTML special characters are in the name', function() {
       testElement = myp5.createSelect(true);
       testElement.option('&', 'foo');
+      assert.equal(testElement.elt.options.length, 1);
       assert.equal(testElement.elt.options[0].value, 'foo');
       testElement.option('&', 'bar');
       assert.equal(testElement.elt.options[0].value, 'bar');