217 lines
3.3 KiB
Markdown
217 lines
3.3 KiB
Markdown
---
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title: RSpec
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category: Ruby
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layout: 2017/sheet
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---
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### About
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{: .-intro}
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RSpec is a Ruby library for testing.
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- <https://rspec.info/>
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### Invoking tests
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```sh
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rake -T spec # List spec tasks
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rake spec # Run all
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rake spec/models/mymodel_spec.rb
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rake spec/models/mymodel_spec.rb:27
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```
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## Writing tests
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```rb
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describe "A User (in general)" do
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include UserSpecHelper
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subject { Person.new }
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let(:admin) { Person.new(role: :admin) }
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context "setter methods" do
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it "should do this" do
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pending "some other thing"
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expect(subject.name).to eq 'x'
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end
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end
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end
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```
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### Before/after
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```rb
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before :each do
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# before all tests
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end
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before do
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# before this suite
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end
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after do
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# after this suite
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end
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```
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### Subjects
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```rb
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subject { CheckingAccount.new }
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it { is_expected.to be_empty }
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# also names: subject(:account) { ... }
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```
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## Expectations
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```rb
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target.should eq 1
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target.should_not eq 1
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expect(target).to eq 1
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expect(target).not_to eq 1
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```
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### Numeric
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```rb
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expect(5).to be < 6
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expect(5).to == 5
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expect(5).to equal value
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expect(5).to be_between(1, 10)
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expect(5).to be_within(0.05).of value
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```
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### Compound expectations
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```rb
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expect(1).to (be < 2).or be > 5
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```
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Use `or`/`and` to string multiple matchers together. See: [Compound expectations](https://relishapp.com/rspec/rspec-expectations/docs/compound-expectations)
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### Comparison
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```rb
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expect(x).to be value
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expect(x).to satisfy { |arg| ... }
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expect(x).to match /regexp/
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```
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### Predicate
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```rb
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expect(x).to be_zero # FixNum#zero?
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expect(x).to be_empty # Array#empty?
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expect(x).to have_key # Hash#has_key?
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```
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### Objects
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```rb
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expect(obj).to be_an_instance_of MyClass
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expect(obj).to be_a_kind_of MyClass
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expect(obj).to respond_to :save!
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```
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### Control flow
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```rb
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expect { user.save! }.to raise_error
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expect { user.save! }.to raise_error(ExceptionName, /msg/)
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expect { user.save! }.to throw :symbol
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```
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### Enumerables/arrays
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```rb
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expect(list).to include(<object>)
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expect(list).to have(1).things
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expect(list).to have_at_least(2).things
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expect(list).to have_at_most(3).things
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expect(list).to have(2).errors_on(:field)
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```
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### Change
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```rb
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expect { thing.approve! }.to \
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change(thing, :status)
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.from(Status::AWAITING_APPROVAL)
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.to(Status::APPROVED)
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expect { thing.destroy }.to \
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change(Thing, :count)
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.by(-1)
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```
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## Doubles
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```rb
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book = double('book')
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book = instance_double('Book', pages: 250)
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```
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### Method stubs
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```rb
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allow(die).to receive(:roll)
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allow(die).to receive(:roll) { 3 }
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allow_any_instance_of(Die).to receive(:roll)
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expect(die).to receive(:roll)
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.with(1)
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.with(1, true)
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.with(boolean)
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.with(anything)
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.with(any_args)
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.with(1, any_args)
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.with(no_args)
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.with(hash_including(a: 1))
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.with(hash_excluding(a: 1))
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.with(array_including(:a, :b))
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.with(array_excluding(:a, :b))
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.with(instance_of(Fixnum))
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.with(kind_of(Numeric))
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.with(<matcher>)
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.once
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.twice
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.exactly(n).times
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.at_least(:once)
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.at_least(:twice)
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.at_least(n).times
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.at_most(:once)
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.at_most(:twice)
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.at_most(n).times
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```
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https://relishapp.com/rspec/rspec-mocks/docs
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## Spec helpers
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```rb
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module UserSpecHelper
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def valid_user_attributes
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{ :email => "joe@bloggs.com",
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:username => "joebloggs",
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:password => "abcdefg"}
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end
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end
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```
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```rb
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describe User do
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include UserSpecHelper
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...
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end
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```
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