MQE-421: Create Unit Tests for the object model

- Add a test for both selector and locatorFunction null

Author: tomreece

dev/tests/unit/Magento/FunctionalTestFramework/Page/Objects/ElementObjectTest.php

@@ -46,13 +46,21 @@ public function testTimeoutCastFromString()
         $this->assertInternalType('int', $timeout);
     }
 
-
     /**
      * An exception should be thrown if both a selector and locatorFunction are passed
      */
     public function testBothSelectorAndLocatorFunction()
     {
         $this->expectException(XmlException::class);
-        new ElementObject('name', 'type', 'selector', 'cantDoThis', 'helloString', true);
+        new ElementObject('name', 'type', 'selector', 'cantHaveThisAndSelector', '-', false);
+    }
+
+    /**
+     * An exception should be thrown if neither a selector nor locatorFunction are passed
+     */
+    public function testNeitherSelectorNorLocatorFunction()
+    {
+        $this->expectException(XmlException::class);
+        new ElementObject('name', 'type', null, null, '-', false);
     }
 }

src/Magento/FunctionalTestingFramework/Page/Objects/ElementObject.php

@@ -68,9 +68,10 @@ class ElementObject
      */
     public function __construct($name, $type, $selector, $locatorFunction, $timeout, $parameterized)
     {
-        //Elements cannot have both a selector and a locatorFunction defined
         if ($selector != null && $locatorFunction != null) {
             throw new XmlException("Element '{$name}' cannot have both a selector and a locatorFunction.");
+        } elseif ($selector == null && $locatorFunction == null) {
+            throw new XmlException("Element '{$name}' must have either a selector or a locatorFunction.'");
         }
 
         $this->name = $name;