Rspec::Parameterized::Core

rspec-parameterized-core provides parameterized test syntax in rspec.

Installation

# Install all components
group :test do
  gem "rspec-parameterized", ">= 1.0.0"
end

# Install only rspec-parameterized-core
group :test do
  gem "rspec-parameterized-core", ">= 1.0.0"
end

Usage

Nested Array Style

describe "plus" do
  where(:a, :b, :answer) do
    [
      [1 , 2 , 3],
      [5 , 8 , 13],
      [0 , 0 , 0]
    ]
  end
  with_them do
    it "should do additions" do
      expect(a + b).to eq answer
    end
  end
  with_them do
    # Can browse parameters via `params` method in with_them block
    # Can browse all parameters via `all_params` method in with_them block
    it "#{params[:a]} + #{params[:b]} == #{params[:answer]}" do
      expect(a + b).to eq answer
    end
  end
end

Hash and Array Style

# Given parameters is each value combinations
# On this case
# [
#   [1, 5, 2],
#   [1, 5, 4],
#   [1, 7, 2],
#   [1, 7, 4],
#   [1, 9, 2],
#   [1, 9, 4],
#   [3, 5, 2],
#   [3, 5, 4],
#   [3, 7, 2],
#   [3, 7, 4],
#   [3, 9, 2],
#   [3, 9, 4]
# ]
describe "Hash arguments" do
  where(a: [1, 3], b: [5, 7, 9], c: [2, 4])
  with_them do
    it "sums is even" do
      expect(a + b + c).to be_even
    end
  end
end

Verbose Syntax

# For complex inputs or if you just want to be super explicit
describe "Verbose syntax" do
  where do
    {
      "positive integers" => {
        a: 1,
        b: 2,
        answer: 3,
      },
      "negative_integers" => {
        a: -1,
        b: -2,
        answer: -3,
      },
      "mixed_integers" => {
        a: 3,
        b: -3,
        answer: 0,
      },
    }
  end
  with_them do
    it "should do additions" do
      expect(a + b).to eq answer
    end
  end
end

Custom names

# It's also possible to override each combination name using magic variable :case_name
# Output:
# Custom names for regular syntax
#   positive integers
#     should do additions
#   negative integers
#     should do additions
#   mixed integers
#     should do additions
describe "Custom names for regular syntax" do
  where(:case_name, :a, :b, :answer) do
    [
      ["positive integers",  6,  2,  8],
      ["negative integers", -1, -2, -3],
      [   "mixed integers", -5,  3, -2],
    ]
  end
  with_them do
    it "should do additions" do
      expect(a + b).to eq answer
    end
  end
end
# Or :case_names lambda for hash syntax
# Output:
# Custom naming for hash syntax
#   1 + 5 + 2
#     sum is even
#   1 + 5 + 4
#     sum is even
#   1 + 7 + 2
#     sum is even
#   ...
describe "Custom naming for hash syntax" do
  where(case_names: ->(a, b, c){"#{a} + #{b} + #{c}"}, a: [1, 3], b: [5, 7, 9], c: [2, 4])
  with_them do
    it "sum is even" do
      expect(a + b + c).to be_even
    end
  end
end

lazy and ref types

# Use ref(:symbol) to use let/let! defined variables in the where block
# Use lazy when you want to create let/let! variables after the where block
#
# Failures will be more readable in the future - https://github.com/tomykaira/rspec-parameterized/pull/65
describe "lazy and ref types" do
  let(:one) { 1 }
  let(:four) { 4 }
  where(:a, :b, :result) do
    [
      [ref(:one), ref(:four), lazy { two + three }]
    ]
  end
  with_them do
    context "use let after where block" do
      let(:two) { 2 }
      let(:three) { 3 }
      it 'should equal 5' do
        expect(a + b).to eq result
      end
    end
  end
end

I was inspired by udzura's mock.

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 the created tag, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/rspec-parameterized/rspec-parameterized-core.

License

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