Add Test for the Interface.

[amanchhaparia]

Is your feature request related to a problem? Please describe.
To verify the proper functionality of the container, test cases are necessary for it. Improper/ Undefined behaviour of the container in some cases might lead to more debugging efforts/inconvenience while developing lower pass.

Describe the solution you'd like
For Interface we can use simple Google Tests.

Additional context
Ref: Buddy Compiler Test Example