Allow to set default values in requests issued by a tdhttp.TestAPI

[c-roussel]

Hi,

On one of my projects there are a lot of tests using always a testAPI with the same set of headers such as:

var defaultHeaders http.Header
testAPI.Post("/my/route", json.RawMessage(`{}`),  defaultsHeaders).
  CmpStatus(http.StatusCreated).
  CmpJSONBody(...)

< Same last 3 lines over and over > 

I wonder if it'd be possible to directly set this kind of default values inside the testAPI itself, such as:

testAPI := tdhttp.NewTestAPI(t, testRouter).DefaultRequestParams(<INSERT DEFAULT HEADERS HERE>)
testAPI.Post("/my/route", json.RawMessage(`{}`)).
  CmpStatus(http.StatusCreated).
  CmpJSONBody(...)

< Same last 3 lines over and over > 

[maxatome]

Good idea, please take a look at #258 to see whether it matches your needs... or not...