如何使用自定义匹配器干燥（这些）RSpec测试

Question

I currently have the following tests, which look like good candidates for a little DRY treatment:

describe League do

  context 'attributes validation' do
    before(:each) do
      @league = League.new
    end

    it 'should be invalid without a short_name' do
      @league.attributes = valid_league_attributes.except(:short_name)
      @league.should_not be_valid
      @league.should have(1).error_on(:short_name)
      @league.errors[:short_name].should == ["can't be blank"]
      @league.short_name = 'NFL'
      @league.should be_valid
    end

    it 'should be invalid without a long_name' do
      @league.attributes = valid_league_attributes.except(:long_name)
      @league.should_not be_valid
      @league.should have(2).error_on(:long_name)
      @league.errors[:long_name].should == ["can't be blank", 'is not included in the list']
      @league.long_name = 'National Football League'
      @league.should be_valid
    end
  end

end

Is it possible to make this more DRY using Custom Matchers or some other utility?

Answer 1

It is possible, but I wouldn't recommend it. These two tests are sufficiently different that writing a method to wrap them into introduces more complexity than seems justified, and will make troubleshooting harder if one of the two tests should ever fail.

Answer 2

You might want to have a look at shoulda

This would allow you to write

describe League do
  subject {League.new}

  it {should validate_presence_of(:long_name)}
  it {should validate_presence_of(:short_name)}
end

There's a bunch of other matchers for validations and associations too.