Fix null integration

config/reek.yml

@@ -127,6 +127,7 @@ UtilityFunction:
   - Mutant::Actor::Env#new_mailbox
   - Mutant::AST::Sexp#s
   - Mutant::CLI#reporter
+  - Mutant::Integration::Null#call
   - Mutant::Integration::Rspec#parse_example
   - Mutant::Meta::Example::Verification#format_mutation
   - Mutant::Reporter::CLI::Format::Progressive#new_buffer

lib/mutant/integration.rb

@@ -77,6 +77,23 @@ module Mutant
         EMPTY_ARRAY
       end
 
+      # Return report for test
+      #
+      # @param [Enumerable<Mutant::Test>] tests
+      #
+      # @return [Result::Test]
+      #
+      # @api private
+      #
+      def call(tests)
+        Result::Test.new(
+          tests:   tests,
+          output:  '',
+          runtime: 0.0,
+          passed:  true
+        )
+      end
+
     end # Null
 
   end # Integration

lib/mutant/integration/rspec.rb

@@ -41,7 +41,7 @@ module Mutant
       #
       # @param [Enumerable<Mutant::Test>] tests
       #
-      # @return [Test::Result]
+      # @return [Result::Test]
       #
       # @api private
       #

spec/unit/mutant/integration_spec.rb

@@ -16,11 +16,28 @@ RSpec.describe Mutant::Integration::Null do
 
   let(:object) { described_class.new }
 
-  describe '#setup' do
+  describe '#all_tests' do
     subject { object.all_tests }
 
     it { should eql([]) }
 
     it_should_behave_like 'an idempotent method'
   end
+
+  describe '#call' do
+    let(:tests) { double('Tests') }
+
+    subject { object.call(tests) }
+
+    it 'returns test result' do
+      should eql(
+        Mutant::Result::Test.new(
+          tests:   tests,
+          runtime: 0.0,
+          passed:  true,
+          output:  ''
+        )
+      )
+    end
+  end
 end