spec/unit/mutest/matcher/methods/instance_spec.rb
RSpec.describe Mutest::Matcher::Methods::Instance, '#call' do
  let(:object) { described_class.new(class_under_test) }
  let(:env)    { Fixtures::TEST_ENV                    }

  let(:class_under_test) do
    parent =
      Module.new do
        def method_d
        end

        def method_e
        end
      end

    Class.new do
      include parent

      private :method_d

      def method_a
      end

      protected

      def method_b
      end

      private

      def method_c
      end
    end
  end

  let(:subject_a) { instance_double(Mutest::Subject) }
  let(:subject_b) { instance_double(Mutest::Subject) }
  let(:subject_c) { instance_double(Mutest::Subject) }
  let(:subjects)  { [subject_a, subject_b, subject_c] }

  before do
    {
      method_a: subject_a,
      method_b: subject_b,
      method_c: subject_c
    }.each do |method, subject|
      matcher = instance_double(Mutest::Matcher)
      expect(matcher).to receive(:call).with(env).and_return([subject])

      expect(Mutest::Matcher::Method::Instance).to receive(:new)
        .with(class_under_test, class_under_test.instance_method(method))
        .and_return(matcher)
    end
  end

  it 'returns expected subjects' do
    expect(object.call(env)).to eql(subjects)
  end
end
