Go Nil Dereference Error When Testing HTTP Request - go

Question

I am trying to test a HTTP request in my Go library. Object which makes the call accepts a HTTP client object via dependency injection so in my test I am mocking the HTTP client like this:
func TestMyObject(t *testing.T) {
server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(200)
w.Header().Set("Content-Type", "application/json")
fmt.Fprintln(w, mockJSONResponse)
}))
defer server.Close()
// Make a transport that reroutes all traffic to the example server
transport := &http.Transport{
Proxy: func(req *http.Request) (*url.URL, error) {
return url.Parse(server.URL)
},
}
// Make a http.Client with the transport
httpClient := &http.Client{Transport: transport}
// I am passing the httpClient to my object
}
Here is how the HTTP request is made within my object:
// Make - makes a prepared HTTP request
func (ir *MyObject) Make() *http.Response {
if ir.Err != nil {
return nil
}
ir.resp, ir.Err = ir.Client.Do(ir.req)
runtime.SetFinalizer(ir, func(ir *MyObject) {
ir.resp.Body.Close()
})
ir.logReqRes()
ir.checkErrorResponse()
return ir.resp
}
I am getting nil pointer dereference error though:
panic: runtime error: invalid memory address or nil pointer dereference [recovered]
panic: runtime error: invalid memory address or nil pointer dereference
In this function (I am trying to log the response):
// Logs request and response
func (ir *MyObject) logReqRes() {
log.Print("AAAAAAA")
log.Print(ir.resp)
log.Print("AAAAAAA")
if reqInfo, err := httputil.DumpRequest(ir.req, true); err == nil {
log.Print("Logging request:")
log.Print(string(reqInfo))
}
if respInfo, err := httputil.DumpResponse(ir.resp, true); err == nil {
log.Print("Logging response:")
log.Print(string(respInfo))
}
}
As you can see, ir.resp is nil for some reason. Any ideas?

Answer 1

Ok. I found an issue. Better logging of errors actually showed that my mistake was very simple.
I was passing this as a URL to mocked HTTP client:
host/api/v1/tokens/
Which was resulting in this error:
Post host/api/v1/tokens/: unsupported protocol scheme
Apparently the URL must include a proper HTTP scheme (http://) even when you are using a test server.