I am trying to find out if there is way to test an app design post development , if the development is implemented pixel perfect as per the design specs or not.
Is there a tool that would help testing the above.
This is borderline off-topic, but I'm answering because it's not purely about implementation. It's question about testing designs.
You can easily test pixel perfection using the Firefox add-in called 'Pixel Perfect', which lets you overlay the design spec over the live page. Useful for testing and development. Of course, this will only work for static elements like layout and typography, not interactions or animations.