Fix - Simple, stupid testing framework for Ruby

A talk at Paris.rb @ Le Wagon about the new Fix specing framework, as an alternative to RSpec.

More details: http://www.meetup.com/fr-FR/parisrb/events/220872045/

Video: https://youtu.be/XV6tVZtKMfA

Transcript

1. Fix Simple, stupid testing framework for Ruby March 1, 2016
2. github.com/cyril Cyril Kato twitter.com/cyri_
3. Chess Gungi Shogi Xiangqi
4. Let’s begin with a survey...
5. Who likes RSpec?
7. Even for simple code?
8. Even for simple code? Let’s take an example
9. 0-example/app.rb APP = 42
10. 0-example/app_spec.rb require_relative 'app' require 'rspec' RSpec.describe APP do it { expect(described_class).to be 42 } end
11. 0-example/app_small_test.rb require_relative 'app' fail unless 42.equal?(APP)
12. Both tests are passing: ➜ ruby 0-example/app_small_test.rb ➜ rspec 0-example/app_spec.rb . Finished in 0.00098 seconds 1 example, 0 failures
13. Both tests are passing. But...
14. Testing with RSpec, the result was processed over... rspec 3.4.0 63 LOC
15. Testing with RSpec, the result was processed over... rspec 3.4.0 rspec-core 3.4.3 63 LOC 7 389 LOC +
16. Testing with RSpec, the result was processed over... rspec 3.4.0 rspec-core 3.4.3 rspec-expectations 3.4.0 63 LOC 7 389 LOC 3 917 LOC + +
17. Testing with RSpec, the result was processed over... rspec 3.4.0 rspec-core 3.4.3 rspec-expectations 3.4.0 rspec-mocks 3.4.1 63 LOC 7 389 LOC 3 917 LOC 4 106 LOC + + +
18. Testing with RSpec, the result was processed over... rspec 3.4.0 rspec-core 3.4.3 rspec-expectations 3.4.0 rspec-mocks 3.4.1 rspec-support 3.4.1 63 LOC 7 389 LOC 3 917 LOC 4 106 LOC 1 624 LOC + + + +
19. Testing with RSpec, the result was processed over... rspec 3.4.0 rspec-core 3.4.3 rspec-expectations 3.4.0 rspec-mocks 3.4.1 rspec-support 3.4.1 diff-lcs 1.2.5 63 LOC 7 389 LOC 3 917 LOC 4 106 LOC 1 624 LOC 1 405 LOC + + + + +
20. Testing with RSpec, the result was processed over... rspec 3.4.0 rspec-core 3.4.3 rspec-expectations 3.4.0 rspec-mocks 3.4.1 rspec-support 3.4.1 diff-lcs 1.2.5 63 LOC 7 389 LOC 3 917 LOC 4 106 LOC 1 624 LOC 1 405 LOC + + + + + 18 504 LOC!!
24. In the other case, with Ruby’s fail(*args)
25. 1 LOC
26. Both tests are passing. Butthe second is more relevant.
27. complexity(testing tool) SHOULD be < complexity(code)
28. Code to test Testing tool
29. BTW
31. ANYWAY Here’s another example
32. require 'rspec' RSpec.describe(-42) do describe '#abs' do it { expect(described_class.abs).to equal 42 } end end
33. require 'rspec' RSpec.describe(-42) do describe '#abs' do it { expect(described_class.abs).to equal 42 } end end Same method, but different behavior
34. require 'rspec' RSpec.describe(-42) do describe '#abs' do it { expect(described_class.abs).to equal 42 } end end I don’t care about class or instance methods
35. require 'rspec' RSpec.describe(-42) do describe '#abs' do it { expect(described_class.abs).to equal 42 } end end We need to repeat the code
36. ZOMG FIX new specing framework
37. require 'fix' Fix.describe(-42) do on :abs do it { MUST equal 42 } end end
38. require 'fix' Fix.describe(-42) do on :abs do it { MUST equal 42 } end end The front object
39. require 'fix' Fix.describe(-42) do on :abs do it { MUST equal 42 } end end An event
40. require 'fix' Fix.describe(-42) do on :abs do it { MUST equal 42 } end end A subject
41. require 'fix' Fix.describe(-42) do on :abs do it { MUST equal 42 } end end An absolute requirement
42. RFC 2119 compliant
43. The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY" in this document are to be interpreted as described in RFC 2119.
44. What about code isolation
45. require 'rspec' greeting = 'Hello world!' RSpec.describe greeting do context 'Alice' do before { greeting.gsub!('world', 'Alice') } it { expect(greeting).to eql 'Hello Alice!' } end context 'Bob' do before { greeting.gsub!('world', 'Bob') } it { expect(greeting).to eql 'Hello Bob!' } end end
46. require 'rspec' greeting = 'Hello world!' RSpec.describe greeting do context 'Alice' do before { greeting.gsub!('world', 'Alice') } it { expect(greeting).to eql 'Hello Alice!' } end context 'Bob' do before { greeting.gsub!('world', 'Bob') } it { expect(greeting).to eql 'Hello Bob!' } end end No isolation of the code to avoid the side effects
47. ➜ rspec 2-example/greeting_spec.rb .F Failures: 1) Hello world! Bob should eql "Hello Bob!" Failure/Error: it { expect(greeting).to eql 'Hello Bob!' } expected: "Hello Bob!" got: "Hello Alice!" Finished in 0.01521 seconds 2 examples, 1 failure
48. require 'fix' greeting = 'Hello world!' Fix.describe greeting do context 'Alice' do on :gsub!, 'world', 'Alice' do it { MUST eql 'Hello Alice!' } end end context 'Bob' do on :gsub!, 'world', 'Bob' do it { MUST eql 'Hello Bob!' } end end end
49. ➜ ruby 2-example/greeting_fix.rb .. Ran 2 tests in 0.005775 seconds 100% compliant - 0 infos, 0 failures, 0 errors
50. With Fix, no side effects outside contexts
51. no particular Style Guide
52. Don't make me think
53. describe "#foo" or describe ".foo"?
54. describe or context?
55. it or specify?
56. Don't get me wrong
58. So I decided to rebuild it
59. In a more adequat way
60. github.com/cyril/r_spec and I call it r_spec
62. Well, let’s try it!
63. app = 'OMGLOL' def app.equal?(*) true end require 'rspec' RSpec.describe app do it { expect(app).to be 42 } end
64. app = 'OMGLOL' def app.equal?(*) true end require 'rspec' RSpec.describe app do it { expect(app).to be 42 } end rspec 3-example/strange_app_spec.rb . Finished in 0.00097 seconds 1 example, 0 failures
65. What did you RSpec?
66. app = 'OMGLOL' def app.equal?(*) true end require 'rspec' RSpec.describe app do it { expect(app).to be 42 } end rspec 3-example/strange_app_spec.rb . Finished in 0.00097 seconds 1 example, 0 failures
67. app = 'OMGLOL' def app.equal?(*) true end require 'rspec' RSpec.describe app do it { expect(app).to be 42 } end rspec 3-example/strange_app_spec.rb . Finished in 0.00097 seconds 1 example, 0 failures Let’s fix that!
68. app = 'OMGLOL' def app.equal?(*) true end require 'rspec' RSpec.describe app do it { expect(app).to be 42 } end
69. app = 'OMGLOL' def app.equal?(*) true end require 'r_spec' RSpec.describe app do it { expect(app).to be 42 } end
70. app = 'OMGLOL' def app.equal?(*) true end require 'r_spec' RSpec.describe app do it { expect(app).to be 42 } end rspec 3-example/strange_app_spec.rb F 1. Failure: Expected "OMGLOL" to be 42. /Users/cyril/parisrb/3-example/strange_ app_spec.rb:10:in `block (2 levels) in <top (required)>' Ran 1 tests in 0.000195 seconds 0% compliant - 0 infos, 1 failures, 0 errors
72. Code in the slides github.com/cyril/parisrb
73. Any questions?
74. Happy specing!!!! github.com/fixrb fixrb.dev