Add one or more quantifier mutations

lib/mutest.rb

@@ -96,6 +96,7 @@ def self.ci?
 require 'mutest/mutator/node/regexp/character_type'
 require 'mutest/mutator/node/regexp/end_of_line_anchor'
 require 'mutest/mutator/node/regexp/end_of_string_or_before_end_of_line_anchor'
+require 'mutest/mutator/node/regexp/one_or_more'
 require 'mutest/mutator/node/regexp/zero_or_more'
 require 'mutest/mutator/node/literal'
 require 'mutest/mutator/node/literal/boolean'

lib/mutest/mutator/node/generic.rb

@@ -41,14 +41,17 @@ class Generic < self
           regexp_digit_type
           regexp_eol_anchor
           regexp_eos_ob_eol_anchor
+          regexp_greedy_one_or_more
           regexp_greedy_zero_or_more
           regexp_hex_type
           regexp_nondigit_type
           regexp_nonhex_type
           regexp_nonspace_type
           regexp_nonword_boundary_anchor
           regexp_nonword_type
+          regexp_possessive_one_or_more
           regexp_possessive_zero_or_more
+          regexp_reluctant_one_or_more
           regexp_reluctant_zero_or_more
           regexp_root_expression
           regexp_space_type

lib/mutest/mutator/node/regexp/one_or_more.rb

@@ -0,0 +1,29 @@
+module Mutest
+  class Mutator
+    class Node
+      module Regexp
+        # Mutator for one-or-more quantifier, `+`
+        class OneOrMore < Node
+          MAP = IceNine.deep_freeze(
+            regexp_greedy_one_or_more:     :regexp_greedy_interval,
+            regexp_reluctant_one_or_more:  :regexp_reluctant_interval,
+            regexp_possessive_one_or_more: :regexp_possessive_interval
+          )
+
+          handle(*MAP.keys)
+
+          children :min, :max, :subject
+
+          # Replace `/a+/` with `/a{2,}/`, `/a+?/` with `/a{2,}?/`, and `/a++/` with `/a{2,}+/`
+          #
+          # @return [undefined]
+          def dispatch
+            emit(s(MAP.fetch(node.type), 2, -1, subject))
+            emit_subject_mutations
+            emit(subject)
+          end
+        end # GreedyZeroOrMore
+      end # Regexp
+    end # Node
+  end # Mutator
+end # Mutest

meta/regexp/regexp_one_or_more.rb

@@ -0,0 +1,32 @@
+Mutest::Meta::Example.add :regexp_greedy_one_or_more do
+  source '/\d+/'
+
+  singleton_mutations
+  regexp_mutations
+
+  mutation '/\d/'
+  mutation '/\d{2,}/'
+  mutation '/\D+/'
+end
+
+Mutest::Meta::Example.add :regexp_reluctant_zero_or_more do
+  source '/\d+?/'
+
+  singleton_mutations
+  regexp_mutations
+
+  mutation '/\d/'
+  mutation '/\d{2,}?/'
+  mutation '/\D+?/'
+end
+
+Mutest::Meta::Example.add :regexp_possessive_zero_or_more do
+  source '/\d++/'
+
+  singleton_mutations
+  regexp_mutations
+
+  mutation '/\d/'
+  mutation '/\d{2,}+/'
+  mutation '/\D++/'
+end