Hi Manish
Do you intend the responsive testing of the components you build in authoring context, or as an end consumer of the web page.
The only use case I can think off at the top of my head for the former, would be if you were testing how the AEM authoring environment appears in different devices which is a very very limited use case compared to the latter ( as authoring is typically not done through mobile devices per se )
For the latter, the responsiveness of your site will depend on the final HTML and UI output by your components and you would need to test this final markup.
For custom components created from scratch, the development team ( UI devs and to a degree , AEM Devs ), are responsible for the final markup as they create the spec. AEM simply allows any HTML5 based content to be rendered but has no control on the markup you produce as such
For custom components based on existing OOB components, the markup injected will be based on what's there in the OOB Component. This may or may not be suitable for your UI Design standards.
Essentially: What ends up on the markup on the final rendered page, depends on your developers .
You could use any framework to test the responsive design of the rendered content