Rspec::NonDeterministicLet

The aim of this gem is easy and intuitive writing with multi precondition specs.

Installation

Add this line to your application's Gemfile:

gem 'rspec-non-deterministic-let'

And then execute:

$ bundle

Or install it yourself as:

$ gem install rspec-non-deterministic-let

Usage

How to use your project

Rails

Please add spec/rails_helper.rb

require 'rspec/non_deterministic_let'

Other

Please add spec/spec_helper.rb

require 'rspec/non_deterministic_let'

Simple case

You can write that code in spec.

RSpec.describe 'Some test'do
  nd_let(:some_state) { 1 }
  nd_let(:some_state) { 2 }

  nd_let_context :some_state do
    it 'some_state = 1 or 2' do
      expect(some_state).to be >= 1
      expect(some_state).to be <= 2
    end
    it 'some_state only 1 or 2' do
      expect(some_state).not_to be < 1
      expect(some_state).not_to be > 2
    end
  end
end

It is same as this code. (but context message is different)

RSpec.describe 'Some test without this gem'do

  shared_examples 'some_state is 1 or 2' do
    it 'some_state = 1 or 2' do
      expect(some_state).to be >= 1
      expect(some_state).to be <= 2
    end
    it 'some_state only 1 or 2' do
      expect(some_state).not_to be < 1
      expect(some_state).not_to be > 2
    end
  end

  context 'some_state = 1' do
    let(:some_state) { 1 }
    include_examples 'some_state is 1 or 2' 
  end

  context 'some_state = 2' do
    let(:some_state) { 2 }
    include_examples 'some_state is 1 or 2' 
  end
end

I think that before one is more intuitive.

spec/rspec/examples_spec.rb contain these examples.

Description

If you want to description with nd_let then you can set description using by second argument.

RSpec.describe 'Some test use by description' do
  nd_let(:some_state, 'some_state = 1') { 1 }
  nd_let(:some_state, 'some_state = 2') { 2 }

  nd_let_context :some_state do
    it 'some_state = 1 or 2' do
      expect(some_state).to be >= 1
      expect(some_state).to be <= 2
    end
    it 'some_state only 1 or 2' do
      expect(some_state).not_to be < 1
      expect(some_state).not_to be > 2
    end
  end
end

This example is exactry same as Some test without this gem case.

nd_let!

You can use nd_let!. The effect of 'nd_let!' is same as let! for let

RSpec.describe 'Some test'do
  nd_let!(:some_state) { 1 }
  nd_let!(:some_state) { 2 }

  nd_let_context :some_state do
    it 'some_state = 1 or 2' do
      expect(some_state).to be >= 1
      expect(some_state).to be <= 2
    end
    it 'some_state only 1 or 2' do
      expect(some_state).not_to be < 1
      expect(some_state).not_to be > 2
    end
  end
end

It is same as this code. (but context message is different)

RSpec.describe 'Some test without this gem'do

  shared_examples 'some_state is 1 or 2' do
    it 'some_state = 1 or 2' do
      expect(some_state).to be >= 1
      expect(some_state).to be <= 2
    end
    it 'some_state only 1 or 2' do
      expect(some_state).not_to be < 1
      expect(some_state).not_to be > 2
    end
  end

  context 'some_state = 1' do
    let!(:some_state) { 1 }
    include_examples 'some_state is 1 or 2' 
  end

  context 'some_state = 2' do
    let!(:some_state) { 2 }
    include_examples 'some_state is 1 or 2' 
  end
end

Multi variable context

If you want to write under case

RSpec.describe 'Direct multi variable context' do
  nd_let(:some_state1, 'some_state1 = 1') { 1 }
  nd_let(:some_state1, 'some_state1 = 2') { 2 }
  nd_let(:some_state2, 'some_state2 = 3') { 3 }
  nd_let(:some_state2, 'some_state2 = 4') { 4 }

  nd_let_context :some_state1 do
    nd_let_context :some_state2 do
      it 'some_state1 = 1 or 2' do
        expect(some_state1).to be >= 1
        expect(some_state1).to be <= 2 end
      it 'some_state1 only 1 or 2' do
        expect(some_state1).not_to be < 1
        expect(some_state1).not_to be > 2
      end

      it 'some_state2 = 3 or 4' do
        expect(some_state2).to be >= 3
        expect(some_state2).to be <= 4
      end
      it 'some_state2 only 3 or 4' do
        expect(some_state2).not_to be < 3
        expect(some_state2).not_to be > 4
      end
    end
  end
end

You can use that code.

RSpec.describe 'multi variable context' do
  nd_let(:some_state1, 'some_state1 = 1') { 1 }
  nd_let(:some_state1, 'some_state1 = 2') { 2 }
  nd_let(:some_state2, 'some_state2 = 3') { 3 }
  nd_let(:some_state2, 'some_state2 = 4') { 4 }

  nd_let_context :some_state1, :some_state2 do
    it 'some_state1 = 1 or 2' do
      expect(some_state1).to be >= 1
      expect(some_state1).to be <= 2
    end
    it 'some_state1 only 1 or 2' do
      expect(some_state1).not_to be < 1
      expect(some_state1).not_to be > 2
    end

    it 'some_state2 = 3 or 4' do
      expect(some_state2).to be >= 3
      expect(some_state2).to be <= 4
    end
    it 'some_state2 only 3 or 4' do
      expect(some_state2).not_to be < 3
      expect(some_state2).not_to be > 4
    end
  end
end

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/[USERNAME]/rspec-non-deterministic-let. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the Rspec::Non::Deterministic::Let project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.