msxml3: Add IDispatchEx test.

dlls/msxml3/tests/domdoc.c

@@ -1877,6 +1877,7 @@ static void test_IXMLDOMDocument2(void)
     BSTR str;
     IXMLDOMDocument *doc;
     IXMLDOMDocument2 *doc2;
+    IDispatchEx *dispex;
     VARIANT var;
     int ref;
 
@@ -1895,6 +1896,13 @@ static void test_IXMLDOMDocument2(void)
     ok( r == S_OK, "ret %08x\n", r );
     ok( doc == (IXMLDOMDocument*)doc2, "interfaces differ\n");
 
+    r = IXMLDOMDocument_QueryInterface( doc, &IID_IDispatchEx, (void**)&dispex );
+    ok( r == S_OK, "ret %08x\n", r );
+    if(r == S_OK)
+    {
+        IDispatchEx_Release(dispex);
+    }
+
     /* we will check if the variant got cleared */
     ref = IXMLDOMDocument2_AddRef(doc2);
     expect_eq(ref, 3, int, "%d");  /* doc, doc2, AddRef*/