expect(method, url, [data], [headers], [keys]);
Creates a new request expectation. 
Parameters
Param Type Details  method   string   HTTP method.   url   stringRegExpfunction(string)   HTTP url or function that receives a url and returns true if the url matches the current definition.   data (optional)   stringRegExpfunction(string)Object   HTTP request body or function that receives data string and returns true if the data is as expected, or Object if request body is in JSON format.   headers