Stub out RoundTripper to test HTTP client

client_test.go

type roundTripFunc func (r *http.Request) (*http.Response, error)

func (s roundTripFunc) RoundTrip(r *http.Request) (*http.Response, error) {
	return s(r)
}

func TestSword(t *testing.T) {
	var c Client
	c.Client.Transport = roundTripFunc(func(r *http.Request) (*http.Response, error) {
		assert.Equal(t, r.URL.Path, "/v1/item/sword")
		return &http.Response{
			StatusCode: http.StatusOK,
			Body: ioutil.NopCloser(strings.NewReader(`{"type":"sword"}`)),
		}, nil
	})
	item, err := c.GetItem(ctx, "sword")
	assert.Nil(t, err)
	assert.Equal(t, item.Type, "sword")
}