Fix style

.rubocop.yml

@@ -5,4 +5,6 @@ AllCops:
     - 'Gemfile.devtools'
     - 'vendor/**/*'
     - 'tmp/**/*'
+    - 'test_app/**/*'
     - 'benchmarks/**/*'
+    - 'bin/mutant'

config/flay.yml

@@ -1,3 +1,3 @@
 ---
 threshold: 18
-total_score: 1191
+total_score: 1198

config/rubocop.yml

@@ -1,18 +1,5 @@
 inherit_from: ../.rubocop.yml
 
-# General note about rubocop.
-# It does NOT allow to silence a specific rule violation.
-# For that reason I sometimes have to disable a whole cop where
-# I just tried to whitelist a specific occurrence.
-
-
-AllCops:
-  Include:
-    - '../**/*.rake'
-    - 'Gemfile'
-    - 'Gemfile.triage'
-    - 'mutant.gemspec'
-
 # Avoid parameter lists longer than five parameters.
 ParameterLists:
   Max: 3
@@ -30,53 +17,31 @@ CollectionMethods:
     find:     'detect'
     find_all: 'select'
 
-# Use square brackets for literal Array objects
-PercentLiteralDelimiters:
-  PreferredDelimiters:
-    '%':  ()
-    '%i': '[]'
-    '%q': ()
-    '%Q': ()
-    '%r': '{}'
-    '%s': ()
-    '%w': '[]'
-    '%W': '[]'
-    '%x': ()
-
-MethodLength:
-  CountComments: false
-  Max: 17 # TODO: Bring down to 10
-
-RegexpLiteral: # I do not agree %r(\A) is more readable than /\A/
+# Do not force public/protected/private keyword to be indented at the same
+# level as the def keyword. My personal preference is to outdent these keywords
+# because I think when scanning code it makes it easier to identify the
+# sections of code and visually separate them. When the keyword is at the same
+# level I think it sort of blends in with the def keywords and makes it harder
+# to scan the code and see where the sections are.
+AccessModifierIndentation:
   Enabled: false
 
-Eval:
-  Enabled: false # Mutant must use Kernel#eval to inject mutated source
-
 # Limit line length
 LineLength:
-  Max: 124  # TODO: lower to 79
+  Max: 120
 
 # Disable documentation checking until a class needs to be documented once
 Documentation:
   Enabled: false
 
+# Do not always use &&/|| instead of and/or.
+AndOr:
+  Enabled: false
+
 # Do not favor modifier if/unless usage when you have a single-line body
 IfUnlessModifier:
   Enabled: false
 
-# Mutant needs to define methods like def bar; end in specs
-Semicolon:
-  Enabled: false
-
-# Mutant needs to define multiple methods on same line in specs
-EmptyLineBetweenDefs:
-  Enabled: false
-
-# Mutant needs to define singleton methods like Foo.bar in specs
-ClassMethods:
-  Enabled: false
-
 # Allow case equality operator (in limited use within the specs)
 CaseEquality:
   Enabled: false
@@ -89,33 +54,63 @@ ConstantName:
 TrivialAccessors:
   Enabled: false
 
-# And also have a different opinion here
-AndOr:
+# Allow empty lines around class body
+EmptyLinesAroundClassBody:
   Enabled: false
 
-# I like my raise
-SignalException:
+# Allow empty lines around module body
+EmptyLinesAroundModuleBody:
   Enabled: false
 
-# I need to chain optparse builder, else it is more ugly
-MultilineBlockChain:
+# Allow empty lines around block body
+EmptyLinesAroundBlockBody:
   Enabled: false
 
-ClassLength:
-  Max: 119
-
-# I align private keywords with class body
-IndentationWidth:
+# Allow multiple line operations to not require indentation
+MultilineOperationIndentation:
   Enabled: false
 
-# I like to have an empty line before closing the currently opened body
-EmptyLinesAroundBody:
+# Prefer String#% over Kernel#sprintf
+FormatString:
   Enabled: false
 
-# I test this style for a while
+# Use square brackets for literal Array objects
+PercentLiteralDelimiters:
+  PreferredDelimiters:
+    '%':  '{}'
+    '%i': '[]'
+    '%q': ()
+    '%Q': ()
+    '%r': '{}'
+    '%s': ()
+    '%w': '[]'
+    '%W': '[]'
+    '%x': ()
+
+# Align if/else blocks with the variable assignment
+EndAlignment:
+  AlignWith: variable
+
+# Do not always align parameters when it is easier to read
+AlignParameters:
+  Exclude:
+    - spec/**/*_spec.rb
+
+# Prefer #kind_of? over #is_a?
+ClassCheck:
+  EnforcedStyle: kind_of?
+
+# Do not prefer double quotes to be used when %q or %Q is more appropriate
+UnneededPercentQ:
+  Enabled: false
+
+# Allow a maximum ABC score
+Metrics/AbcSize:
+  Max: 18.00
+
+# Do not prefer lambda.call(...) over lambda.(...)
 LambdaCall:
   Enabled: false
 
-# I like my style more
-AccessModifierIndentation:
-  Enabled: false
+Style/RegexpLiteral:
+  MaxSlashes: 0

lib/mutant.rb

@@ -74,6 +74,8 @@ module Mutant
   #
   # @api private
   #
+  # rubocop:disable MethodLength
+  #
   def self.singleton_subclass_instance(name, superclass, &block)
     klass = Class.new(superclass) do
       def inspect

lib/mutant/ast.rb

@@ -15,7 +15,7 @@ module Mutant
     # @api private
     #
     def self.walk(node, stack, &block)
-      raise ArgumentError, 'block expected' unless block_given?
+      fail ArgumentError, 'block expected' unless block_given?
 
       block.call(node, stack)
       node.children.grep(Parser::AST::Node).each do |child|

lib/mutant/cli.rb

@@ -74,7 +74,7 @@ module Mutant
 
       parse_match_expressions(opts.parse!(arguments))
     rescue OptionParser::ParseError => error
-      fail(Error, error.message, error.backtrace)
+      raise(Error, error.message, error.backtrace)
     end
 
     # Parse matchers
@@ -101,6 +101,8 @@ module Mutant
     #
     # @api private
     #
+    # rubocop:disable MethodLength
+    #
     def add_environment_options(opts)
       opts.separator('Environment:')
       opts.on('--zombie', 'Run mutant zombified') do
@@ -129,7 +131,7 @@ module Mutant
       require "mutant/integration/#{name}"
       update(integration: Integration.lookup(name))
     rescue LoadError
-      fail Error, "Could not load integration #{name.inspect} (you may want to try installing the gem mutant-#{name})"
+      raise Error, "Could not load integration #{name.inspect} (you may want to try installing the gem mutant-#{name})"
     end
 
     # Add options
@@ -146,7 +148,8 @@ module Mutant
 
       opts.on('--score COVERAGE', 'Fail unless COVERAGE is not reached exactly') do |coverage|
         update(expected_coverage: Float(coverage))
-      end.on('--use STRATEGY', 'Use STRATEGY for killing mutations', &method(:setup_integration))
+      end
+      opts.on('--use STRATEGY', 'Use STRATEGY for killing mutations', &method(:setup_integration))
     end
 
     # Add filter options
@@ -177,12 +180,15 @@ module Mutant
     def add_debug_options(opts)
       opts.on('--fail-fast', 'Fail fast') do
         update(fail_fast: true)
-      end.on('--version', 'Print mutants version') do
+      end
+      opts.on('--version', 'Print mutants version') do
         puts("mutant-#{Mutant::VERSION}")
         Kernel.exit(EXIT_SUCCESS)
-      end.on('-d', '--debug', 'Enable debugging output') do
+      end
+      opts.on('-d', '--debug', 'Enable debugging output') do
         update(debug: true)
-      end.on_tail('-h', '--help', 'Show this message') do
+      end
+      opts.on_tail('-h', '--help', 'Show this message') do
         puts(opts.to_s)
         Kernel.exit(EXIT_SUCCESS)
       end

lib/mutant/env.rb

@@ -125,7 +125,7 @@ module Mutant
     def expression(scope)
       name = scope_name(scope) or return
 
-      unless name.is_a?(String)
+      unless name.instance_of?(String)
         warn("#{scope.class}#name from: #{scope.inspect} returned #{name.inspect}. #{SEMANTICS_MESSAGE}")
         return
       end

lib/mutant/isolation.rb

@@ -17,7 +17,7 @@ module Mutant
       def self.call(&block)
         block.call
       rescue => exception
-        fail Error, exception
+        raise Error, exception
       end
     end
 
@@ -37,6 +37,8 @@ module Mutant
       #
       # @api private
       #
+      # rubocop:disable MethodLength
+      #
       def self.call(&block)
         reader, writer = IO.pipe.map(&:binmode)
 
@@ -52,7 +54,7 @@ module Mutant
         writer.close
         Marshal.load(reader.read)
       rescue => exception
-        fail Error, exception
+        raise Error, exception
       ensure
         Process.waitpid(pid) if pid
       end

lib/mutant/loader.rb

@@ -12,6 +12,10 @@ module Mutant
       #
       # @api private
       #
+      # One off the very few valid uses of eval
+      #
+      # rubocop:disable Lint/Eval
+      #
       def call
         eval(
           source,

lib/mutant/matcher/compiler.rb

@@ -42,6 +42,8 @@ module Mutant
       #
       # @api private
       #
+      # rubocop:disable MethodLength
+      #
       def predicate
         if subject_selector && subject_rejector
           Morpher::Evaluator::Predicate::Boolean::And.new([

lib/mutant/mutation.rb

@@ -16,6 +16,8 @@ module Mutant
     #
     # @api private
     #
+    # rubocop:disable MethodLength
+    #
     def kill(isolation, integration)
       start = Time.now
       tests = subject.tests

lib/mutant/mutator/node/const.rb

@@ -19,7 +19,7 @@ module Mutant
           emit_singletons unless parent_node && n_const?(parent_node)
           emit_type(nil, *children.drop(1))
           children.each_with_index do |child, index|
-            mutate_child(index) if child.is_a?(Parser::AST::Node)
+            mutate_child(index) if child.instance_of?(Parser::AST::Node)
           end
         end
 

lib/mutant/mutator/node/generic.rb

@@ -26,7 +26,7 @@ module Mutant
         #
         def dispatch
           children.each_with_index do |child, index|
-            mutate_child(index) if child.is_a?(Parser::AST::Node)
+            mutate_child(index) if child.instance_of?(Parser::AST::Node)
           end
         end
 

lib/mutant/parallel/master.rb

@@ -43,6 +43,8 @@ module Mutant
       #
       # @api private
       #
+      # rubocop:disable MethodLength
+      #
       def run
         config.jobs.times do
           @workers += 1

lib/mutant/reporter/cli.rb

@@ -14,13 +14,11 @@ module Mutant
       #
       def self.build(output)
         tty = output.respond_to?(:tty?) && output.tty?
-        format =
-          if !Mutant.ci? && tty && Tput::INSTANCE.available
-            Format::Framed.new(tty:  tty, tput: Tput::INSTANCE)
-          else
-            Format::Progressive.new(tty: tty)
-          end
-
+        format = if !Mutant.ci? && tty && Tput::INSTANCE.available
+          Format::Framed.new(tty:  tty, tput: Tput::INSTANCE)
+        else
+          Format::Progressive.new(tty: tty)
+        end
         new(output, format)
       end
 

lib/mutant/reporter/cli/printer.rb

@@ -176,7 +176,7 @@ module Mutant
           # @api private
           #
           def active_subject_results
-            active_mutation_jobs = active_jobs.select { |job| job.payload.is_a?(Mutant::Mutation) }
+            active_mutation_jobs = active_jobs.select { |job| job.payload.kind_of?(Mutant::Mutation) }
             active_subjects = active_mutation_jobs.map(&:payload).flat_map(&:subject).to_set
 
             payload.subject_results.select do |subject_result|
@@ -197,6 +197,8 @@ module Mutant
           #
           # @api private
           #
+          # rubocop:disable AbcSize
+          #
           def run
             info 'Mutant configuration:'
             info 'Matcher:         %s',      object.matcher_config.inspect
@@ -231,6 +233,8 @@ module Mutant
           #
           # @api private
           #
+          # rubocop:disable MethodLength
+          #
           def run
             visit(Config, env.config)
             info 'Subjects:        %s',        amount_subjects
@@ -480,7 +484,8 @@ module Mutant
 
           delegate :mutation, :test_result
 
-          DIFF_ERROR_MESSAGE = 'BUG: Mutation NOT resulted in exactly one diff hunk. Please report a reproduction!'.freeze
+          DIFF_ERROR_MESSAGE =
+            'BUG: Mutation NOT resulted in exactly one diff hunk. Please report a reproduction!'.freeze
 
           MAP = {
             Mutant::Mutation::Evil    => :evil_details,

lib/mutant/zombifier/file.rb

@@ -10,6 +10,10 @@ module Mutant
       #
       # @api private
       #
+      # Probably one of the only valid uses of eval.
+      #
+      # rubocop:disable Lint/Eval
+      #
       def zombify(namespace)
         $stderr.puts("Zombifying #{path}")
         eval(
@@ -33,15 +37,7 @@ module Mutant
       # @api private
       #
       def self.find(logical_name)
-        file_name =
-          case ::File.extname(logical_name)
-          when '.so'
-            return
-          when '.rb'
-            logical_name
-          else
-            "#{logical_name}.rb"
-          end
+        file_name = expand_file_name(logical_name)
 
         $LOAD_PATH.each do |path|
           path = Pathname.new(path).join(file_name)
@@ -52,6 +48,29 @@ module Mutant
         nil
       end
 
+      # Return expanded file name
+      #
+      # @param [String] logical_name
+      #
+      # @return [nil]
+      #   if no expansion is possible
+      #
+      # @return [String]
+      #
+      # @api private
+      #
+      def self.expand_file_name(logical_name)
+        case ::File.extname(logical_name)
+        when '.so'
+          return
+        when '.rb'
+          logical_name
+        else
+          "#{logical_name}.rb"
+        end
+      end
+      private_class_method :expand_file_name
+
     private
 
       # Return node

spec/support/corpus.rb

@@ -47,6 +47,8 @@ module Corpus
     #   otherwise
     #
     # rubocop:disable MethodLength
+    # rubocop:disable AbcSize
+    #
     def verify_mutation_generation
       checkout
       start = Time.now

spec/support/fake_actor.rb

@@ -12,7 +12,7 @@ module FakeActor
 
     def verify(other)
       unless eql?(other)
-        raise "Got:\n#{other.inspect}\nExpected:\n#{inspect}"
+        fail "Got:\n#{other.inspect}\nExpected:\n#{inspect}"
       end
       block.call(other.message) if block
     end
@@ -31,16 +31,16 @@ module FakeActor
     end
 
     def sending(expectation)
-      raise "Unexpected send: #{expectation.inspect}" if messages.empty?
+      fail "Unexpected send: #{expectation.inspect}" if messages.empty?
       expected = messages.shift
       expected.verify(expectation)
       self
     end
 
     def receiving(name)
-      raise "No message to read for #{name.inspect}" if messages.empty?
+      fail "No message to read for #{name.inspect}" if messages.empty?
       expected = messages.shift
-      raise "Unexpected message #{expected.inspect} for #{name.inspect}" unless expected.name.eql?(name)
+      fail "Unexpected message #{expected.inspect} for #{name.inspect}" unless expected.name.eql?(name)
       expected.message
     end
 

spec/support/mutation_verifier.rb

@@ -43,6 +43,8 @@ private
   #
   # @api private
   #
+  # rubocop:disable AbcSize
+  #
   def mutation_report
     message = ['Original-AST:', original_node.inspect, 'Original-Source:', Unparser.unparse(original_node)]
     if missing.any?

spec/support/shared_context.rb

@@ -8,12 +8,13 @@ module SharedContext
   def messages(&block)
     let(:message_sequence) do
       FakeActor::MessageSequence.new.tap do |sequence|
-         sequence.instance_eval(&block)
+        sequence.instance_eval(&block)
       end
     end
   end
 
   # rubocop:disable MethodLength
+  # rubocop:disable AbcSize
   def setup_shared_context
     let(:env)              { double('env', config: config, subjects: [subject_a], mutations: mutations) }
     let(:job_a)            { Mutant::Parallel::Job.new(index: 0, payload: mutation_a)                   }

spec/unit/mutant/env_spec.rb

@@ -8,11 +8,13 @@ RSpec.describe Mutant::Env do
       it 'warns via reporter' do
         klass = Class.new do
           def self.name
-            raise
+            fail
           end
         end
 
-        expected_warnings = ["Class#name from: #{klass} raised an error: RuntimeError. #{Mutant::Env::SEMANTICS_MESSAGE}"]
+        expected_warnings = [
+          "Class#name from: #{klass} raised an error: RuntimeError. #{Mutant::Env::SEMANTICS_MESSAGE}"
+        ]
 
         expect { subject }.to change { config.reporter.warn_calls }.from([]).to(expected_warnings)
 

spec/unit/mutant/expression_spec.rb

@@ -51,7 +51,10 @@ RSpec.describe Mutant::Expression do
       let(:input) { 'foo bar' }
 
       it 'raises an exception' do
-        expect { subject }.to raise_error(Mutant::Expression::InvalidExpressionError, 'Expression: "foo bar" is not valid')
+        expect { subject }.to raise_error(
+          Mutant::Expression::InvalidExpressionError,
+          'Expression: "foo bar" is not valid'
+        )
       end
     end
 

spec/unit/mutant/warning_filter_spec.rb

@@ -54,7 +54,7 @@ RSpec.describe Mutant::WarningFilter do
     it 'executes block with warning filter enabled' do
       found = false
       object.use do
-        found = $stderr.is_a?(described_class)
+        found = $stderr.instance_of?(described_class)
       end
       expect(found).to be(true)
     end
@@ -71,6 +71,7 @@ RSpec.describe Mutant::WarningFilter do
 
     it 'returns warnings generated within block' do
       warnings = object.use do
+        # rubocop:disable Lint/Eval
         eval(<<-RUBY)
           Class.new do
             def foo