Tests are extremely importante in software development. This talk bring a quick introduction to the art of testing in Go, given a special focus on the standard lib, but also giving a quick glance at other alternatives.

1. Testing in Go
TDC 2016 - São Paulo
Eduardo Bonet

2. $ whoami
ebonet.me

3. Agenda
Objectives
The Testing package
Table Testing
Testing HTTP
Other Testing Packages

4. Objectives
Present the basis for efficient test in Go focusing on the standard library, but with
a quick glance at some alternatives.

5. Why Testing?
Improves focus while developing
Avoids breaking old cold
Verify if machines are working properly
Documentation
…….

6. go test
go test // testing the local package
go test some/pkg // testing a specific package
go test -v some/pkg -run ^TestSum$ // runs the specified tests
go test --cover // Code coverage
https://golang.org/src/cmd/go/test.go

7. Testing in Go
Tests are written on files ending with "_test.go"
A Test is a function that starts with Test* and has only the parameter *testing.T

8. Plugin support for tests

9. Plugin support for tests
Atom (go-plus) Vim (vim-go) IntelliJ
Running full suites
Run specific test
Code Coverage
Others Keybindings for quick
switch

10. Vim-go
Coverage

11. Test Results
vim-go

12. Coverage
IntelliJ

13. Test Results
IntelliJ

14. Example: Simplified Blackjack

15. Simplified BlackJack
Uses a deck.
Cards from 2 to 9 are worth their face value
Figures worth 10 points
Ace is worth 11 points
Ace + Figure = Blackjack
If over 21, the hand is busted.

16. Implementing testing - Score Computation
A Hand is represented by a string, where each char represents a card ("AJ" is a
blackjack)

17. [master] blackjack_test.go

18. [master] blackjack_test.go

19. REPETITIO
N
[master] blackjack_test.go

20. Table Testing
Using anonymous structs to represent test cases

21. [master] blackjack_test.go

23. [master] blackjack_test.go

24. [master] blackjack_test.go

25. [master] blackjack_test.go

26. Auxiliary Functions
Testing Floats
[master] main_test.go

27. Auxiliary Functions
Testing Floats
[master] main_test.go
PRECISÃO
NUM
ÉRICA

28. Auxiliary Functions
Testing Floats
[master] main_test.go

29. Auxiliary Functions
valor, existe := mapa["key"]
[master] main_test.go

30. Testing HTTP - BlackJack
Let's create a simple BlackJack API that computes the hand result:
GET /blackjack
● Parameters
○ hand [string] : the hand
● Returns
○ [422], if 'hand' is not found or invalid
○ [200, result] if 'hand' is valid

31. Testing HTTP - BlackJack
[master] blackjack.go

32. Testing HTTP - BlackJack
https://golang.org/pkg/net/http/httptest/
Utililty package to test http.
Provides the struct *ResponseRecorder, that implements the interface
*ResponseWriter

33. Testing HTTP - BlackJack
[master] blackjack_test.go

34. Testando HTTP - BlackJack
[master] blackjack_test.go

35. Other Packages

36. Ginkgo
http://onsi.github.io/ginkgo/ (1075 )
BDD
Works with go test, but has it's own structure
Uses a custom lib for assertion (Gomega)
Rerun testes on change

37. ginkgo
Testing Scoring [code]

38. ginkgo
Table Testing [code]

39. Ginkgo - Results

40. GoConvey
http://goconvey.co/ (2334 )
BDD alike
Pretty browser interface
Reload tests on file changes
Custom DSL

41. goconvey
Testing Scoring [code]

42. goconvey
Table Testing [code]

43. goconvey
Results

44. goconvey
Failed test

45. Testify
https://github.com/stretchr/testify (2025 )
Run within go test
Additional testing functionality, mostly shortcuts
Mocking

46. Conclusion
Testing in go is very easy
For microservices, the standard library is more than sufficient
For larger apps, GoConvey or Ginkgo can speed up development process and
documentation, at the cost of losing integration with IDEs

47. Thank you!
Slides at ebonet.me/talks
Code at github.com/ebonet/gotesting