Introduction to automated tests (Goiania)

Transcript

1. Introduction to Automated Tests Gabriel Sobrinho
2. GABRIEL SOBRINHO gabrielsobrinho.com twitter.com/sobrinho github.com/sobrinho speakerdeck.com/sobrinho
3. We are hiring! become@codeminer42.com
5. Concepts
6. Software
7. Software is a set of instructions instructing a computer to do specific tasks
8. Bug
9. A software bug is an error in a program that causes it to produce an incorrect result or misbehave unintentionally
15. All of these failures are due to poor design, coding and testing
16. Tests are the answer to avoid these kind of failures
17. How?
19. Human Tester
20. Normally done by the QA department, a person who exercises the software
22. Automated Tests
23. A software that compares actual outcomes with predicted outcomes
24. Ensure code quality
25. Avoid regressions
26. Reduce maintenance cost
27. Code and behaviour documentation
29. Examples
30. def sum(a, b) a + b end
31. if sum(1, 2) == 3 puts 'success' else abort 'failure' end
32. $ ruby test.rb success
34. Methodologies
35. Test-Driven Development
36. Write tests before the code itself to get fast feedback and guidance
39. Examples
40. if sum_all([1, 2, 3]) == 6 puts 'sucess' else abort 'failure' end
41. $ ruby tdd.rb tdd.rb:1:in `<main>': undefined method `sum_all’ for main:Object (NoMethodError)
42. def sum_all end
43. $ ruby tdd.rb tdd.rb:1:in `sum_all': wrong number of arguments (given 1, expected 0) (ArgumentError) from tdd.rb:4:in `<main>'
44. def sum_all(numbers) end
45. $ ruby tdd.rb failure
46. def sum_all(numbers) total = 0 numbers.each do |number| total += number end total end
47. $ ruby tdd.rb success
48. def sum_all(numbers) total = 0 numbers.each do |number| total += number end total end
49. def sum_all(numbers) numbers.reduce(:+) end
50. $ ruby tdd.rb success
53. Behavior-Driven Development
54. BDD is a subset of TDD that enforces the story telling format to be clear about the expectations
55. TDD focuses on each and every unit test for every function, doesn't matter what it does https://softwareengineering.stackexchange.com/a/224102
56. BDD focuses on software that matters https://softwareengineering.stackexchange.com/a/224102
58. Feature: Calculator As Einstein I want a calculator So I can perform basic operations Scenario: Subtraction Given I have two numbers When I subtract them Then I want the difference
59. Given 'I have two numbers' do @a = 6 @b = 3 end When 'I subtract them' do @result = subtract(@a, @b) end Then 'I want the difference' do assert @result == 3 end
60. Feature: Calculator As Einstein I want a calculator So I can perform basic operations Scenario: Subtraction Given I have two numbers When I subtract them undefined method `subtract' for #<Object: 0x00007fd094cb5018> (NoMethodError) calc.rb:7:in `/^I\ subtract\ them$/' calc.feature:8:in `When I subtract them' Then I want the difference Failing Scenarios: cucumber calc.feature:6 # Scenario: Subtraction 1 scenario (1 failed) 3 steps (1 failed, 1 skipped, 1 passed) 0m0.021s
61. def subtract end
62. Feature: Calculator As Einstein I want a calculator So I can perform basic operations Scenario: Subtraction Given I have two numbers When I subtract them wrong number of arguments (given 2, expected 0) (ArgumentError) calc.rb:1:in `subtract' calc.rb:10:in `/^I\ subtract\ them$/' calc.feature:8:in `When I subtract them' Then I want the difference Failing Scenarios: cucumber calc.feature:6 # Scenario: Subtraction 1 scenario (1 failed) 3 steps (1 failed, 1 skipped, 1 passed) 0m0.021s
63. def subtract(a, b) end
64. Feature: Calculator As Einstein I want a calculator So I can perform basic operations Scenario: Subtraction Given I have two numbers When I subtract them SolidAssert::AssertionFailedError (SolidAssert::AssertionFailedError) calc.rb:14:in `/^I\ want\ the\ difference$/' calc.feature:9:in `Then I want the difference' Then I want the difference Failing Scenarios: cucumber calc.feature:6 # Scenario: Subtraction 1 scenario (1 failed) 3 steps (1 failed, 1 skipped, 1 passed) 0m0.021s
65. def subtract(a, b) a - b end
66. Feature: Calculator As Einstein I want a calculator So I can perform basic operations Scenario: Subtraction Given I have two numbers When I subtract them Then I want the difference 1 scenario (1 passed) 3 steps (3 passed) 0m0.019s
69. Types
70. Unit Testing
71. Tests about the smallest piece of the software isolated from the real world
72. Integrated Testing
73. Tests using connected pieces of the software like databases and APIs
74. describe ZipCode do it 'returns the street information' do # Triggers a HTTP API call zip_code = ZipCode.find('12345') expect(zip_code.number).to eq '12345' expect(zip_code.street).to eq 'Some Avenue' end end
75. Acceptance Testing
76. Tests if the software works as the customer or stakeholder expects
77. You may open the browser and click on a button and expect something to happen
78. feature 'Buy' do scenario 'Buy a product using credit card' do visit '/products/1' click_on 'Buy' expect(page).to have_content 'Order made' expect(credit_card).to have_charged 14.99 end end
80. Artifacts
81. Code to Test Ratio How many lines of production code there are against lines of test code
82. Code Coverage Percentage of the code that was exercised during the test suite
84. Recommendations
85. Write unit tests, integrated tests and acceptance tests
86. You can write tests before or after writing the code but write tests
87. You can use BDD, TDD or whatever as long you have a methodology
88. Use TDD for unit and integrated tests and BDD for acceptance tests
89. Write tests that asserts the collateral effect and not the implementation
90. Be Happy!
92. Thanks!
93. Questions?
94. Thanks!
95. We are hiring! become@codeminer42.com
97. • http://www.devmedia.com.br/artigo-engenharia-de-software-3-a-importancia-dos-testes- automatizados/9532 • http://www.eduardopires.net.br/2012/06/ddd-tdd-bdd/ • http://tdd.caelum.com.br • https://cbabhusal.wordpress.com/2016/02/26/tdd-why-red-green-refactor-is-important-in-tdd/ • https://ciclosw.wordpress.com/2014/09/04/diferenca-entre-tdd-e-bdd/ • http://blog.locaweb.com.br/artigos/metodologias-ageis/diferenca-entre-bdd-tdd/ • https://www.infoq.com/news/2015/02/bdd-ddd • http://www.princiweb.com.br/blog/programacao/tdd/tdd-ddd-e-bdd-praticas-de- desenvolvimento.html • http://www.agileandart.com/2010/07/16/ddd-introducao-a-domain-driven-design/ References