diff --git a/src/common/services/OptionsService.test.ts b/src/common/services/OptionsService.test.ts
index 59c17faf..a42220fe 100644
--- a/src/common/services/OptionsService.test.ts
+++ b/src/common/services/OptionsService.test.ts
@@ -3,7 +3,7 @@
  * @license MIT
  */
 
-import { assert } from 'chai';
+import { assert, expect } from 'chai';
 import { OptionsService, DEFAULT_OPTIONS } from 'common/services/OptionsService';
 
 describe('OptionsService', () => {
@@ -19,4 +19,42 @@ describe('OptionsService', () => {
       assert.equal(new OptionsService({tabStopWidth: 0}).getOption('tabStopWidth'), DEFAULT_OPTIONS.tabStopWidth);
     });
   });
+  describe('setOption', () => {
+    let service: OptionsService;
+    beforeEach(() => {
+      service = new OptionsService({});
+    });
+    it('applies valid fontWeight option values', () => {
+      service.setOption('fontWeight', 'bold');
+      assert.equal(service.getOption('fontWeight'), 'bold', '"bold" keyword value should be applied');
+
+      service.setOption('fontWeight', 'normal');
+      assert.equal(service.getOption('fontWeight'), 'normal', '"normal" keyword value should be applied');
+
+      service.setOption('fontWeight', '600');
+      assert.equal(service.getOption('fontWeight'), '600', 'String numeric values should be applied');
+
+      service.setOption('fontWeight', 350);
+      assert.equal(service.getOption('fontWeight'), 350, 'Values between 1 and 1000 should be applied as is');
+
+      service.setOption('fontWeight', 1);
+      assert.equal(service.getOption('fontWeight'), 1, 'Range should include minimum value: 1');
+
+      service.setOption('fontWeight', 1000);
+      assert.equal(service.getOption('fontWeight'), 1000, 'Range should include maximum value: 1000');
+    });
+    it('normalizes invalid fontWeight option values', () => {
+      service.setOption('fontWeight', 350);
+      expect(() => service.setOption('fontWeight', 10000)).to.not.throw('', 'fontWeight should be normalized instead of throwing');
+      assert.equal(service.getOption('fontWeight'), DEFAULT_OPTIONS.fontWeight, 'Values greater than 1000 should be reset to default');
+
+      service.setOption('fontWeight', 350);
+      service.setOption('fontWeight', -10);
+      assert.equal(service.getOption('fontWeight'), DEFAULT_OPTIONS.fontWeight, 'Values less than 1 should be reset to default');
+
+      service.setOption('fontWeight', 350);
+      service.setOption('fontWeight', 'bold700');
+      assert.equal(service.getOption('fontWeight'), DEFAULT_OPTIONS.fontWeight, 'Wrong string literals should be reset to default');
+    });
+  });
 });