The document discusses unit testing APIs by mocking dependencies, illustrated through a Go code example that defines a user storage interface and a user service. It emphasizes the importance of accepting interfaces and returning structs in API design. Multiple links to best practices and resources on testing in Go are also provided.

2. Testando API's de forma unitária
mocando as dependências.

3. Marcelo Aymone
Desenvolvedor de software na
Neoway

4. “Accept interfaces, return structs.”

5. type userStorage interface {
Get(id string) (*domain.User, error)
Insert(user *domain.User) (*domain.User, error)
}
type userService struct {
storage userStorage
}
func NewService(s userStorage) *userService {
return &userService{
storage: s,
}
}

6. func (u *userService) FindID(id string) (*domain.User, error) {
return u.storage.Get(id)
}
func (u *userService) Create(user *domain.User) (*domain.User, error) {
if err := user.Validate(); err != nil {
return nil, err
}
return u.storage.Insert(user)
}

10. type userStorageMock struct {
GetFn func(id string) (*domain.User, error)
InsertFn func(user *domain.User) (*domain.User, error)
}
func (s *userStorageMock) Get(id string) (*domain.User, error) {
return s.GetFn(id)
}
func (s *userStorageMock) Insert(user *domain.User) (*domain.User, error) {
return s.InsertFn(user)
}

11. expectedId := "userID"
userMock := &userStorageMock{
GetFn: func(id string) (*domain.User, error) {
assert.Equal(t, expectedId, id)
return &domain.User{
ID: id,
}, nil
},
}
userService := user.NewService(userMock)

14. Integração
Unidade
Lento
RápidoUnitários
Integração
Aceitação
Manual

17. Links
http://idiomaticgo.com/post/best-practice/accept-interfaces-return-structs/
https://medium.com/@cep21/what-accept-interfaces-return-structs-means-in-go-2fe879e25ee8
https://martinfowler.com/articles/practical-test-pyramid.html
https://blog.golang.org/cover
https://travis-ci.org/
https://goreportcard.com/
https://codeclimate.com/

18. Marcelo Bertholdt Aymone
mbaymone@gmail.com
linkedin.com/in/marceloaymone
github.com/aymone/api-unit-test