tea-time/presentation/04_expect.slides

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# `expect`

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# What should we get as an output?

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``` coffeescript
describe 'Cat', ->
  describe '#meow', ->
    it 'should meow correctly', ->
      expect(cat.meow()).toEqual('meow')
```

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# Wait, we need a cat.

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``` coffeescript
describe 'Cat', ->
  describe '#meow', ->
    it 'should meow correctly', ->
      cat = new Cat()

      expect(cat.meow()).toEqual('meow')
```

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``` coffeescript
# code-under-test

class @Cat
  meow: ->
```

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``` javascript
// safety wrapper to prevent global pollution
(function() {
  this.Cat = (function() {
    function Cat() {}
    Cat.prototype.meow = function() {};
    return Cat;
  })();
})(this) // this is window in a browser
```

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# Run it!

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```
1 spec, 1 failure

Expected undefined to equal 'meow'.
```

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# Make it meow!

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``` coffeescript
class @Cat
  meow: -> "meow"
```

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```
1 spec, 0 failures
```

!SLIDE
# Here's what you should have meow...

!SLIDE even-larger
``` coffeescript
# spec

describe 'Cat', ->
  describe '#meow', ->
    it 'should meow correctly', ->
      expect(cat.meow()).toEqual('meow')
```

!SLIDE even-larger
``` coffeescript
# code-under-test

class @Cat
  meow: -> "meow"
```