diff --git a/tests/unit/font.spec.js b/tests/unit/font.spec.js
index 67241554..33e19d6a 100644
--- a/tests/unit/font.spec.js
+++ b/tests/unit/font.spec.js
@@ -1,5 +1,6 @@
-import PDFFontFactory from '../../lib/font_factory';
 import PDFDocument from '../../lib/document';
+import PDFFontFactory from '../../lib/font_factory';
+import { logData } from './helpers';
 
 describe('EmbeddedFont', () => {
   test('no fontLayoutCache option', () => {
@@ -52,4 +53,46 @@ describe('EmbeddedFont', () => {
       expect(dictionary.data.BaseFont).toBe('BAJJZZ+Roboto-Regular');
     });
   });
+
+  describe.only('toUnicodeMap', () => {
+    test('bfrange lines should not cross highcode boundary', () => {
+      const doc = new PDFDocument({ compress: false });
+      const font = PDFFontFactory.open(
+        doc,
+        'tests/fonts/Roboto-Regular.ttf',
+        undefined,
+        'F1099'
+      );
+
+      // 398 different glyphs
+      font.encode('ABCDEFGHIJKLMNOPQRSTUVWXYZ');
+      font.encode('abcdefghijklmnopqrstuvwxyz');
+      font.encode('ÁÀÂÄÅÃÆÇÐÉÈÊËÍÌÎÏÑÓÒÔÖÕØŒÞÚÙÛÜÝŸ');
+      font.encode('áàâäãåæçðéèêëíìîïıñóòôöõøœßþúùûüýÿ');
+      font.encode('ĀĂĄĆČĎĐĒĖĘĚĞĢĪĮİĶŁĹĻĽŃŅŇŌŐŔŖŘŠŚŞȘŢȚŤŪŮŰŲŽŹŻ');
+      font.encode('āăąćčďđēėęěğģīįķłĺļľńņňōőŕŗřšśşșţțťūůűųžźż');
+      font.encode('ΑΒΓ∆ΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΩΆΈΉΊΌΎΏΪΫ');
+      font.encode('αβγδεζηθικλµνξοπρςστυφχψωάέήίόύώϊϋΐΰ');
+      font.encode('АБВГДЕЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯ');
+      font.encode('абвгдежзийклмнопрстуфхцчшщъыьэюя');
+      font.encode('ЀЁЂЃЄЅІЇЈЉЊЋЌЍЎЏҐӁҒҖҚҢҮҰҲҶҺӘӢӨӮ');
+      font.encode('ѐёђѓєѕіїјљњћќѝўџґӂғҗқңүұҳҷһәӣөӯ');
+
+      const docData = logData(doc);
+      font.toUnicodeCmap();
+      const text = docData.map((d) => d.toString("utf8")).join("");
+
+      let glyphs = 0
+      for (const block of text.matchAll(/beginbfrange\n((?:.|\n)*?)\nendbfrange/g)) {
+        for (const line of block[1].matchAll(/^<([0-9a-f]+)>\s+<([0-9a-f]+)>\s+\[/igm)) {
+          const low = parseInt(line[1], 16);
+          const high = parseInt(line[2], 16);
+          glyphs += high - low + 1;
+          expect(high & 0xFFFFFF00).toBe(low & 0xFFFFFF00);
+        }
+      }
+
+      expect(glyphs).toBe(398 + 1);
+    });
+  });
 });