describe Rake::Funnel::Support::Patch do
  describe 'without definition' do
    it 'should be applicable' do
      subject.apply!
    end

    it 'should be revertable' do
      subject.revert!
    end

    it 'should be applicable and revertable' do
      subject.apply!.revert!
    end
  end

  describe 'with definition' do
    subject {
      described_class.new do |p|
        p.setup do
          output.puts 'setup'
          42
        end

        p.reset do |memo|
          output.puts memo
        end
      end
    }

    let(:output) { double.as_null_object }

    context 'when applying the patch' do
      let!(:ret) { subject.apply! }

      it 'should execute the setup' do
        expect(output).to have_received(:puts).with('setup')
      end

      it 'should return self' do
        expect(ret).to eq(subject)
      end
    end

    context 'when reverting the patch' do
      let!(:ret) {
        subject.apply!
        subject.revert!
      }

      it 'should execute the reset' do
        expect(output).to have_received(:puts).with(42)
      end

      it 'should return self' do
        expect(ret).to eq(subject)
      end
    end

    context 'when reverting an unapplied patch' do
      before { subject.revert! }

      it 'should not execute the reset' do
        expect(output).to_not have_received(:puts).with(42)
      end
    end

    context 'when applying twice' do
      before {
        subject.apply!
        subject.apply!
      }

      it 'should execute the setup once' do
        expect(output).to have_received(:puts).with('setup').once
      end
    end

    context 'when reverting twice' do
      before {
        subject.apply!
        subject.revert!
        subject.revert!
      }

      it 'should execute the revert once' do
        expect(output).to have_received(:puts).with(42).once
      end
    end

    describe 'context' do
      let(:context) { 42 }

      subject {
        described_class.new(context) do |p|
          p.setup do |context|
            output.puts context
          end
        end
      }

      before { subject.apply!.revert! }

      it 'should be accessible from within the patch definition' do
        expect(output).to have_received(:puts).with(42)
      end
    end
  end
end