Add kwoptarg mutations

config/flay.yml

@@ -1,3 +1,3 @@
 ---
 threshold: 16
-total_score: 1160
+total_score: 1166

lib/mutant/mutator/node/argument.rb

@@ -37,7 +37,12 @@ module Mutant
         # Mutator for optional arguments
         class Optional < self
 
-          handle(:optarg)
+          TYPE_MAP = IceNine.deep_freeze(
+            optarg:   :arg,
+            kwoptarg: :kwarg
+          )
+
+          handle(:optarg, :kwoptarg)
 
           children :name, :default
 
@@ -56,7 +61,7 @@ module Mutant
           #
           # @return [undefined]
           def emit_required_mutation
-            emit(s(:arg, name))
+            emit(s(TYPE_MAP.fetch(node.type), name))
           end
 
         end # Optional

lib/mutant/mutator/node/generic.rb

@@ -9,7 +9,7 @@ module Mutant
         # your contribution is that close!
         handle(
           :ensure, :redo, :regopt, :retry, :arg_expr, :blockarg,
-          :kwrestarg, :kwoptarg, :undef, :module, :empty,
+          :kwrestarg, :undef, :module, :empty,
           :alias, :for, :xstr, :back_ref, :class, :restarg,
           :sclass, :match_with_lvasgn, :while_post,
           :until_post, :preexe, :postexe, :iflipflop, :eflipflop, :kwsplat,

meta/kwoptarg.rb

@@ -1,4 +1,4 @@
-Mutant::Meta::Example.add :kwoptarg do
+Mutant::Meta::Example.add :kwarg do
   source 'def foo(bar: baz); end'
 
   mutation 'def foo; end'
@@ -6,4 +6,6 @@ Mutant::Meta::Example.add :kwoptarg do
   mutation 'remove_method(:foo)'
   mutation 'def foo(bar: nil); end'
   mutation 'def foo(bar: self); end'
+  mutation 'def foo(bar:); end'
+  mutation 'def foo(_bar: baz); end'
 end