Add regexp mutation for \Z -> \z

config/flay.yml

@@ -1,3 +1,3 @@
 ---
 threshold: 16
-total_score: 1303
+total_score: 1306

lib/mutant.rb

@@ -94,6 +94,7 @@ require 'mutant/mutator/node/regexp'
 require 'mutant/mutator/node/regexp/alternation_meta'
 require 'mutant/mutator/node/regexp/character_type'
 require 'mutant/mutator/node/regexp/end_of_line_anchor'
+require 'mutant/mutator/node/regexp/end_of_string_or_before_end_of_line_anchor'
 require 'mutant/mutator/node/literal'
 require 'mutant/mutator/node/literal/boolean'
 require 'mutant/mutator/node/literal/range'

lib/mutant/mutator/node/generic.rb

@@ -41,6 +41,7 @@ module Mutant
           regexp_bol_anchor
           regexp_digit_type
           regexp_eol_anchor
+          regexp_eos_ob_eol_anchor
           regexp_hex_type
           regexp_nondigit_type
           regexp_nonhex_type

lib/mutant/mutator/node/regexp/end_of_string_or_before_end_of_line_anchor.rb

@@ -0,0 +1,21 @@
+module Mutant
+  class Mutator
+    class Node
+      module Regexp
+        # Mutator for end of line or before end of string anchor `\Z`
+        class EndOfStringOrBeforeEndOfLineAnchor < Node
+          handle(:regexp_eos_ob_eol_anchor)
+
+          # Emit mutations
+          #
+          # Replace `\Z` with `\z`
+          #
+          # @return [undefined]
+          def dispatch
+            emit(s(:regexp_eos_anchor))
+          end
+        end # EndOfLineAnchor
+      end # Regexp
+    end # Node
+  end # Mutator
+end # Mutant

meta/regexp/regexp_eos_ob_eol_anchor.rb

@@ -3,4 +3,6 @@ Mutant::Meta::Example.add :regexp_eos_ob_eol_anchor do
 
   singleton_mutations
   regexp_mutations
+
+  mutation '/\z/'
 end