Make composed_chars_normalized compatible with frozen_string_literal:…

… true (#133)

Co-authored-by: Jane Sandberg <sandbergja@users.noreply.github.com>

lib/marc_cleanup/variable_fields.rb

@@ -469,16 +469,15 @@ def composed_chars_normalize(record)
       field_index = record.fields.index(field)
       curr_subfield = 0
       field.subfields.each do |subfield|
-        fixed_subfield = ''
         prevalue = subfield.value
         if prevalue =~ /^.*[\u0653\u0654\u0655].*$/
           prevalue = prevalue.unicode_normalize(:nfc)
         end
-        prevalue.each_codepoint do |c|
-          char = c.chr(Encoding::UTF_8)
-          char.unicode_normalize!(:nfd) if c < 1570 || (7_680..10_792).cover?(c)
-          fixed_subfield << char
-        end
+        fixed_subfield = prevalue.codepoints.map do |codepoint|
+          char = codepoint.chr(Encoding::UTF_8)
+          char.unicode_normalize!(:nfd) if codepoint < 1570 || (7_680..10_792).cover?(codepoint)
+          char
+        end.join
         record.fields[field_index].subfields[curr_subfield].value = fixed_subfield
         curr_subfield += 1
       end

spec/variable_fields/composed_chars_normalize_spec.rb

@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require 'marc_cleanup'
+ARABIC_STRING = 'يُعَظِّمُونَهُ وَيُؤْمِنُونَ أَنَّهُ'
+
+RSpec.describe 'composed_chars_normalize' do
+  let(:record) { MARC::Record.new_from_hash('fields' => fields, 'leader' => leader) }
+  let(:leader) { '01104naa a2200289 i 4500' }
+  let(:length_of_arabic_string) { ARABIC_STRING.length }
+
+  context 'When the title is in Arabic with NFC' do
+    let(:fields) do
+      [
+         { '245' => { 'ind1' => '', 'ind2' => ' ', 'subfields' => [{ '6' => '880-03' }, { 'a' => ARABIC_STRING.unicode_normalize(:nfc) }] } }
+      ]
+    end
+
+    it 'keeps it in NFC' do
+      expect(composed_chars_normalize(record)['245']['a']).to eq ARABIC_STRING.unicode_normalize(:nfc)
+      expect(ARABIC_STRING.unicode_normalize(:nfc).length).to eq length_of_arabic_string
+    end
+  end
+  context 'When the title is in Arabic with NFD' do
+    let(:fields) do
+      [
+         { '245' => { 'ind1' => '', 'ind2' => ' ', 'subfields' => [{ '6' => '880-03' }, { 'a' => ARABIC_STRING.unicode_normalize(:nfd) }] } }
+      ]
+    end
+
+    it 'normalizes it to NFC' do
+      expect(composed_chars_normalize(record)['245']['a']).to eq ARABIC_STRING.unicode_normalize(:nfc)
+      expect(ARABIC_STRING.unicode_normalize(:nfd).length).not_to eq length_of_arabic_string
+    end
+  end
+end