Remove CLI::Builder registry

lib/mutant/cli.rb

@@ -61,7 +61,7 @@ module Mutant
         debug:             @debug,
         matcher:           matcher,
         subject_predicate: @subject_predicate.output,
-        strategy:          @strategy.output,
+        strategy:          @strategy || Strategy::Null.new,
         fail_fast:         @fail_fast,
         reporter:          reporter
       )
@@ -167,10 +167,8 @@ module Mutant
       parser.separator(EMPTY_STRING)
       parser.separator('Strategies:')
 
-      Builder::REGISTRY.each do |builder, instance_variable_name|
+      builder = Builder::Predicate::Subject.new(@cache, parser)
-        builder = builder.new(@cache, parser)
+      @subject_predicate = builder
-        instance_variable_set(instance_variable_name, builder)
-      end
     end
 
     # Add environmental options
@@ -191,6 +189,22 @@ module Mutant
       end
     end
 
+    # Add runner
+    #
+    # @param [String] runner_name
+    #
+    # @return [undefined]
+    #
+    # @api private
+    #
+    def set_strategy(name)
+      require "mutant/#{name}"
+      @strategy = Strategy.lookup(name).new
+    rescue LoadError
+      $stderr.puts("Cannot load strategy: #{name.inspect}")
+      raise
+    end
+
     # Add options
     #
     # @param [Object] opts
@@ -203,6 +217,10 @@ module Mutant
       opts.separator ''
       opts.separator 'Options:'
 
+      opts.on('--via STRATEGY', 'Use STRATEGY for killing mutations') do |runner|
+        set_strategy(runner)
+      end
+
       opts.on('--version', 'Print mutants version') do |name|
         puts("mutant-#{Mutant::VERSION}")
         Kernel.exit(0)

lib/mutant/cli/builder.rb

@@ -6,18 +6,6 @@ module Mutant
     class Builder
       include AbstractType
 
-      REGISTRY = {}
-
-      # Register builder
-      #
-      # @return [undefined]
-      #
-      # @api private
-      #
-      def self.register(instance_variable_name)
-        REGISTRY[self] = instance_variable_name
-      end
-
       # Return cache
       #
       # @return [Cache]
@@ -71,8 +59,6 @@ module Mutant
         # Bubject predicate builder
         class Subject < self
 
-          register :@subject_predicate
-
           # Initialize object
           #
           # @api private

lib/mutant/killer.rb

@@ -99,5 +99,25 @@ module Mutant
     #
     abstract_method :run
 
+    # Null killer that never kills a mutation
+    class Null < self
+
+    private
+
+      # Run killer
+      #
+      # @return [true]
+      #   when mutant was killed
+      #
+      # @return [false]
+      #   otherwise
+      #
+      # @api private
+      #
+      def run
+        false
+      end
+
+    end
   end # Killer
 end # Mutant

lib/mutant/rspec.rb

@@ -2,7 +2,6 @@ require 'rspec'
 
 require 'mutant/rspec/killer'
 require 'mutant/rspec/strategy'
-require 'mutant/rspec/builder'
 
 module Mutant
   module Rspec

lib/mutant/rspec/builder.rb

@@ -1,51 +0,0 @@
-module Mutant
-  module Rspec
-    # Rspec strategy builder
-    class Builder < CLI::Builder
-
-      register :@strategy
-
-      # Initialize object
-      #
-      # @return [undefined]
-      #
-      # @api private
-      #
-      def initialize(*)
-        @rspec = false
-        super
-      end
-
-      # Return strategy
-      #
-      # @return [Strategy::Rspec]
-      #
-      # @api private
-      #
-      def output
-        unless @rspec
-          raise Error, 'No strategy given'
-        end
-
-        Strategy.new
-      end
-
-    private
-
-      # Add cli options
-      #
-      # @param [OptionParser] parser
-      #
-      # @return [undefined]
-      #
-      # @api private
-      #
-      def add_options
-        parser.on('--rspec', 'kills mutations with rspec') do
-          @rspec = true
-        end
-      end
-
-    end # Builder
-  end # Rspec
-end # Mutant

lib/mutant/rspec/strategy.rb

@@ -4,7 +4,8 @@ module Mutant
   module Rspec
     # Rspec killer strategy
     class Strategy < Mutant::Strategy
-      include Equalizer.new
+
+      register 'rspec'
 
       KILLER = Killer::Forking.new(Rspec::Killer)
 

lib/mutant/strategy.rb

@@ -6,6 +6,34 @@ module Mutant
   class Strategy
     include AbstractType, Adamantium::Flat
 
+    REGISTRY = {}
+
+    # Lookup strategy for name
+    #
+    # @param [String] name
+    #
+    # @return [Strategy]
+    #   if found
+    #
+    # @api private
+    #
+    def self.lookup(name)
+      REGISTRY.fetch(name)
+    end
+
+    # Register strategy
+    #
+    # @param [String] name
+    #
+    # @return [undefined]
+    #
+    # @api private
+    #
+    def self.register(name)
+      REGISTRY[name] = self
+    end
+    private_class_method :register
+
     # Perform strategy setup
     #
     # @return [self]
@@ -50,5 +78,15 @@ module Mutant
       self.class::KILLER
     end
 
+    # Null strategy that never kills a mutation
+    class Null < self
+
+      register 'null'
+
+      KILLER = Killer::Null
+
+    end # Null
+
   end # Strategy
+
 end # Mutant

spec/integration/mutant/rspec_spec.rb

@@ -10,7 +10,7 @@ describe Mutant, 'rspec integration' do
     end
   end
 
-  let(:base_cmd) { 'bundle exec mutant -I lib --require test_app --rspec' }
+  let(:base_cmd) { 'bundle exec mutant -I lib --require test_app --via rspec' }
 
   specify 'it allows to kill mutations' do
     Kernel.system("#{base_cmd} ::TestApp::Literal#string").should be(true)

spec/unit/mutant/rspec/builder_spec.rb

@@ -1,21 +0,0 @@
-# encoding: utf-8
-
-require 'spec_helper'
-
-describe Mutant::Rspec::Builder do
-
-  let(:option_parser) { OptionParser.new }
-
-  let(:cache)  { Mutant::Cache.new                         }
-  let(:object) { described_class.new(cache, option_parser) }
-
-  let(:default_strategy) do
-    Mutant::Rspec::Strategy.new
-  end
-
-  specify do
-    object
-    option_parser.parse!(%w[--rspec])
-    expect(object.output).to eql(default_strategy)
-  end
-end