Add tests for queue.

[codesankalp]

Currently there is a pr for queue implementation but there are no test cases so you have to add the test for this in the queue branch.

what to do:

• [ ] Write tests for pyqueue in tests/
• [ ] make a pull request for queue branch not for master branch.
• [ ] update the queue branch with the master.

[shivsubh]

I want to work on this issue.

[codesankalp]

Ok @shivsubh assigning you. Happy Coding :relaxed: