Port binary method operator mutator to parser

TODO

@@ -18,6 +18,7 @@ Mutations:
   * Emit negative and positive mutations
   * Mutate Block catch "def foo(&block)" and block pass "foo(&block)"
   * Mutate super arguments just like send arguments
+  * Binary operator mutations
   * Add timeout to terminate infinite loops
 
     Example of a negative mutation:

lib/mutant.rb

@@ -58,7 +58,7 @@ require 'mutant/mutator/node/begin'
 require 'mutant/mutator/node/while'
 require 'mutant/mutator/node/super'
 require 'mutant/mutator/node/send'
-require 'mutant/mutator/node/send/binary_operator_method'
+require 'mutant/mutator/node/send/binary'
 require 'mutant/mutator/node/when'
 require 'mutant/mutator/node/assignment'
 require 'mutant/mutator/node/define'

lib/mutant/mutator/node/send.rb

@@ -19,11 +19,29 @@ module Mutant
         # @api private
         #
         def dispatch
+          if binary_operator?
+            run(Binary)
+            return
+          end
           emit(receiver) if receiver
           mutate_receiver
           mutate_arguments
         end
 
+        # Test for binary operator
+        #
+        # @return [true]
+        #   if send is a binary operator
+        #
+        # @return [false]
+        #   otherwise
+        #
+        # @api private
+        #
+        def binary_operator?
+          arguments.one? && BINARY_METHOD_OPERATORS.include?(selector)
+        end
+
         # Mutate arguments
         #
         # @return [undefined]

lib/mutant/mutator/node/send/binary.rb

@@ -0,0 +1,31 @@
+module Mutant
+  class Mutator
+    class Node
+      class Send
+
+        # Mutator for sends that correspond to a binary operator
+        class Binary < self
+
+          RIGHT_INDEX = SELECTOR_INDEX+1
+
+        private
+
+          # Emit mutations
+          #
+          # @return [undefined]
+          #
+          # @api private
+          #
+          def dispatch
+            emit(receiver)
+            mutate_child(RECEIVER_INDEX) # left
+            mutate_child(RIGHT_INDEX)
+            emit(arguments.first)
+          end
+
+        end # Binary
+
+      end # Send
+    end # Node
+  end # Mutator
+end # Mutant

lib/mutant/mutator/node/send/binary_operator_method.rb

@@ -1,62 +0,0 @@
-module Mutant
-  class Mutator
-    class Node
-      class Send
-
-        # Mutator for sends that correspond to a binary operator
-        class BinaryOperatorMethod < Node
-
-        private
-
-          # Emit mutations
-          #
-          # @return [undefined]
-          #
-          # @api private
-          #
-          def dispatch
-            emit_left_mutations
-            emit_right_mutations
-            emit(right)
-          end
-
-          # Emit left mutations
-          #
-          # @return [undefined]
-          #
-          # @api private
-          #
-          def emit_left_mutations
-            emit_attribute_mutations(:receiver)
-          end
-
-          # Return right
-          #
-          # @return [Parser::AST::Node]
-          #
-          # @api private
-          #
-          def right
-            node.arguments.array.first
-          end
-
-          # Emit right mutations
-          #
-          # @return [undefined]
-          #
-          # @api private
-          #
-          def emit_right_mutations
-            Mutator.each(right).each do |mutated|
-              dup = dup_node
-              dup.arguments.array[0] = mutated
-              emit(dup)
-            end
-          end
-
-        end # BinaryOperatorMethod
-
-      end # Send
-    end # Node
-  end # Mutator
-end # Mutant