unit test cases api testing

hello sir,
i was trying to call an back end api from jasmine from spec.ts.i am facing problem my api is not called.please help me how to set up proxy in karama.
i have set proxy server in dev.js so in dev environment it is working fine but in case of test environment
it is throwing errors.
please suggest me how to call api from the spect.ts file in angular 2.0.

thanks
Regards
Byomakesh Dasah