How do I write integration tests for net / http code?

Here's some sample code:

package main

import (
    "net/http"
)

func Home(w http.ResponseWriter, r *http.Request) {
    w.Write([]byte("Hello, world!"))
}

func Router() *http.ServeMux {
    mux := http.NewServeMux()
    mux.HandleFunc("/", Home)
    return mux
}

func main() {
    mux := Router()
    http.ListenAndServe(":8080", mux)
}

      

        
        
        
      

    

This is the test script I wrote:

package main

import (
    "net/http"
    "net/http/httptest"
    "testing"
)

func TestMain(t *testing.T) {
    w := httptest.NewRecorder()
    r, _ := http.NewRequest("GET", "/", nil)
    Router().ServeHTTP(w, r)
    if w.Body.String() != "Hello, world!" {
        t.Error("Wrong content:", w.Body.String())
    }
}

      

        
        
        
      

    

Does this test actually send an HTTP request over a TCP socket and reach the endpoint /

? Or is it just a function call with no HTTP connection?

Update

Based on the answer given by @ffk, I wrote the test like this:

func TestMain(t *testing.T) {
    ts := httptest.NewServer(Router())
    defer ts.Close()
    req, _ := http.NewRequest("GET", ts.URL+"/", nil)
    client := http.Client{}
    resp, _ := client.Do(req)
    defer resp.Body.Close()
    body, _ := ioutil.ReadAll(resp.Body)
    if string(body) != "Hello, world!" {
        t.Error("Wrong content:", string(body))
    }
}