Websocket integration tests - SET and GET

[psrvere]

This PR is a preparatory step in adding integration tests for websocket --> #557. We want to use all async server integration tests as it is for websocket with minor changes.

This PR

• changes websocket FireCommand function to be compatible with async server integration tests
• adds tests for GET command

[psrvere]

@pratikpandey21 @lucifercr07 - Please review.

[psrvere]

@pratikpandey21 - the only change I made was related to types in assert statement. These types are dependent on the parsing logic which will evolve as we ass more tests to it.