type HttpClient interface {
    Do(req *http.Request) (*http.Response, error)
}

func GetOverview(client HttpClient, overview *Overview) (*Overview, error) {

    request, err := http.NewRequest("GET", fmt.Sprintf("%s:%s/api/overview", overview.Config.Url, overview.Config.Port), nil)
    if (err != nil) {
        log.Println(err)
    }
    request.SetBasicAuth(overview.Config.User, overview.Config.Password)
    resp, err := client.Do(request)

type ClientMock struct {
}

func (c *ClientMock) Do(req *http.Request) (*http.Response, error) {
    return &http.Response{}, nil
}

type HttpClient interface {
    Do(req *http.Request) (*http.Response, error)
}

type MockClient struct {
    DoFunc func(req *http.Request) (*http.Response, error)
}

func (m *MockClient) Do(req *http.Request) (*http.Response, error) {
    if m.DoFunc != nil {
        return m.DoFunc(req)
    }
    return &http.Response{}, nil
}