package testpackage

// Run this using $ go test

import (
	"bytes"
	"fmt"
	"io/ioutil"
	"net/http"
	"testing"
)

// RoundTripFuncError describes an interface type that we will then implement.
type RoundTripFuncError func(req *http.Request) *http.Response

// RoundTripError implements Golang's roundtrip interface. In this
// version we want to simulate an error when trying to connect to a
// given SPARQL server.
func (fn RoundTripFuncError) RoundTrip(request *http.Request) (*http.Response, error) {
	return fn(request), fmt.Errorf("Mock error...")
}

// NewTestClientError returns *http.Client with Transport replaced to
// avoid making real calls out to the Internet. Transport will then do
// whatever we request of it. With this version we mock an error in the
// call.
func NewTestClientError(fn RoundTripFuncError) *http.Client {
	return &http.Client{
		Transport: RoundTripFuncError(fn),
	}
}

// TestRoundtrip...
func TestRoundtrip(t *testing.T) {
	httpClient := NewTestClientError(func(req *http.Request) *http.Response {
		return &http.Response{
			StatusCode: 418,
			// Send response to be tested
			Body: ioutil.NopCloser(bytes.NewBufferString("Some response")),
			// Must be set to non-nil value or it panics
			Header: make(http.Header),
		}
	})

	req, err := http.NewRequest("GET", "http://example.com", nil)

	if err != nil {
		// Do something...
	}

	_, err = httpClient.Do(req)
	if err != nil {
		// Do something...
	}
}