Golang HTTP REST mocking

I working on a client that connects to a server (offering a REST endpoint). The client needs to make a chain of 11 different requests to complete an action (it's for a rococo backup system).

I'm writing my client in Golang and I also want to write my mocks in Golang. What I'm unclear about is how a test called func TestTheWorld would call into the client's func main(), to test completion of the chain of 11 requests. Would I compile my client to a binary and then call the binary (and it's environment variables) from the tests?

I'm looking at the Advanced Example in jarcoal/httpmock (but I could use another library). At the end the example says // do stuff that adds and checks articles, is that where I would call my client?

I've pasted the Advanced Example below, for future reference.

---

func TestFetchArticles(t *testing.T) {
    httpmock.Activate()
    defer httpmock.DeactivateAndReset()

    // our database of articles
    articles := make([]map[string]interface{}, 0)

    // mock to list out the articles
    httpmock.RegisterResponder("GET", "http://ift.tt/2xbzGwb",
        func(req *http.Request) (*http.Response, error) {
            resp, err := httpmock.NewJsonResponse(200, articles)
            if err != nil {
                return httpmock.NewStringResponse(500, ""), nil
            }
            return resp, nil
        },
    )

    // mock to add a new article
    httpmock.RegisterResponder("POST", "http://ift.tt/2xbzGwb",
        func(req *http.Request) (*http.Response, error) {
            article := make(map[string]interface{})
            if err := json.NewDecoder(req.Body).Decode(&article); err != nil {
                return httpmock.NewStringResponse(400, ""), nil
            }

            articles = append(articles, article)

            resp, err := httpmock.NewJsonResponse(200, article)
            if err != nil {
                return httpmock.NewStringResponse(500, ""), nil
            }
            return resp, nil
        },
    )

    // do stuff that adds and checks articles
}