Fixed testcase: setting an empty ID should remove the ID.

tests/auto/qml/qmldesigner/coretests/testcore.cpp

@@ -463,18 +463,6 @@ void TestCore::testModelCreateSubNode()
     expectedCalls << TestView::MethodCall("nodeIdChanged", QStringList() << "Blah" << "Blah" << "");
     QCOMPARE(view->methodCalls(), expectedCalls);
 
-    try {
-        childNode.setId("");
-        QFAIL("Setting an invalid id does not throw an exception");
-    } catch (Exception &exception) {
-        QCOMPARE(exception.type(), QString("InvalidIdException"));
-    }
-    try {
-        childNode.setId(QString());
-        QFAIL("Setting an invalid id does not throw an exception");
-    } catch (Exception &exception) {
-        QCOMPARE(exception.type(), QString("InvalidIdException"));
-    }
     try {
         childNode.setId("invalid id");
         QFAIL("Setting an invalid id does not throw an excxeption");
@@ -484,6 +472,9 @@ void TestCore::testModelCreateSubNode()
 
     QCOMPARE(childNode.id(), QString("Blah"));
     QCOMPARE(view->methodCalls(), expectedCalls);
+
+    childNode.setId(QString());
+    QVERIFY(childNode.id().isEmpty());
 }