converter_spec.rb

describe CSVToJSON do
  context '#to_json' do

    let(:dummy) { Class.new { include CSVToJSON } }
    subject { dummy.new }

    it 'changes #read array of arrays to json' do
      expect(subject).to receive(:read).and_return([['header'], ['cell']])
      expect(subject.to_json).to eq 'foo'
    end
  end
end