The Anatomy of a mocked call - RuLu 2014

Transcript

1. The Anatomy of a mocked call
2. !/samphippen
3. Hello everyone :)
4. Why is testing?
5. x`
7. Tests force behaviour
8. Without tests Anything could happen
9. Unit Testing makes me happy :)
10. Stubbing and mocking
11. Stubbing
12. Fake response to a method
13. allow(x).to( receive(:foo).and_return(3) )
14. x.foo will return 3
15. Mocking
16. Testing methods get called
17. expect(x).to receive(:foo)
18. Test fails if x does not receive foo
19. expect(x).to receive(:foo).with(3)
20. expect(x).to( receive(:foo) .with(3) .exactly(4).times )
21. How does it work?
22. Stubs
23. it “does something” do allow(foo).to receive(:bar) expect(foo.bar).to eq(nil) end
24. it “does something” do allow(foo).to receive(:bar) expect(foo.bar).to eq(nil) end
25. allow is syntax sugar for AllowanceTarget.new
26. Allowance Target
27. Allowance Target TargetBase
28. AllowanceTarget calls #delegate_to with :setup_allowance on TargetBase
29. Allowance Target TargetBase
30. TargetBase defines #to on AllowanceTarget
31. Defined #to calls :setup_allowance on matchers passed to #to
32. Allowance Target TargetBase
33. it “does something” do allow(foo).to receive(:bar) expect(foo.bar).to eq(nil) end
34. Things passed to #to are called “matchers”
35. Receive is a commonly used mocking/stubbing matcher
36. AllowanceTarget#to calls setup_allowance on the passed matcher
37. Allowance Target TargetBase Allowance Target TargetBase Receive
38. Receive#setup_allowance creates a Mock Proxy for object
39. Receive#setup_allowance calls #add_stub on the Mock Proxy
40. Allowance Target TargetBase Receive Proxy
41. Proxy objects manage all mocks/stubs for an object
42. it “does something” do allow(foo).to receive(:bar) allow(foo).to receive(:baz) expect(foo.bar).to eq(nil) end
43. Proxy#add_stub creates a MethodDouble for the stubbed method
44. Allowance Target TargetBase Proxy Receive Method Double
45. MethodDouble saves the original implementation
46. MethodDouble creates stub implementation
47. it “does something” do allow(foo).to receive(:bar) expect(foo.bar).to eq(nil) end
48. it “does something” do allow(foo).to receive(:bar) expect(foo.bar).to eq(nil) end
49. foo.bar is the stubbed implementation
50. Call foo.bar
51. Method Double Call foo.bar
52. Method Double Call foo.bar Proxy
53. Method Double Call foo.bar Proxy Invokes stub
54. Method Double Call foo.bar Proxy Invokes stub Return value
55. it “does something” do allow(foo).to receive(:bar) expect(foo.bar).to eq(nil) end
56. RSpec manages lifecycle of mocks
57. RSpec::Mocks.setup
58. RSpec::Mocks.setup Your test
59. RSpec::Mocks.setup Your test RSpec::Mocks.verify
60. RSpec::Mocks.teardown RSpec::Mocks.setup Your test RSpec::Mocks.verify
61. All of this happens in a mock space
62. Allowance Target TargetBase Proxy Receive Method Double
63. RSpec::Mocks.teardown calls #reset_all on the current Space
64. Space#reset_all calls #reset on each proxy
65. Proxy#reset calls #reset on each MethodDouble
66. MethodDouble#reset returns original methods to objects
67. RSpec::Mocks.teardown RSpec::Mocks.setup Your test RSpec::Mocks.verify
68. Phew
69. Mocks
70. it “does something” do expect(foo).to receive(:bar).with(3) expect(foo.bar(3)).to eq(nil) end
71. expect is syntax sugar for ExpectationTarget.new
72. Expectation Target TargetBase Proxy Receive Method Double
73. Calls #setup_expectation
74. it “does something” do expect(foo).to receive(:bar).with(3) expect(foo.bar(3)).to eq(nil) end
75. Receive stores details of stubbed/ mocked implementation
76. Expectation Target TargetBase Proxy Receive Method Double
77. Method Double Call foo.bar Proxy Invokes stub Return value
78. Proxy callback checks arguments
79. Proxy raises if args don’t match
80. it “does something” do expect(foo).to receive(:bar).with(3) expect(foo.bar(3)).to eq(nil) end
81. RSpec::Mocks.teardown RSpec::Mocks.setup Your test RSpec::Mocks.verify
82. RSpec::Mocks.verify calls Space#verify_all
83. Space#verify_all calls #verify on each Proxy
84. Proxy raises if mock not called
85. And that’s how it all works :)
86. RSpec::Mocks.teardown RSpec::Mocks.setup Your test RSpec::Mocks.verify
87. expect(x).to receive(:foo) allow(x).to receive(:foo)
88. Target TargetBase
89. expect(x).to receive(:foo) allow(x).to receive(:foo)
90. Target TargetBase
91. expect(x).to receive(:foo) allow(x).to receive(:foo)
92. Receive
93. Proxy Receive
94. Proxy Receive Method Double
95. Target TargetBase Proxy Receive Method Double
96. Method Double Call foo.bar Proxy Invokes stub Return value
97. Target TargetBase Proxy Receive Method Double
98. RSpec 3.0.0 is out Please use it
99. tinyurl.com/ samrl2014
100. Let’s have some questions !/samphippen sam@funandplausible.com