diff --git a/app/comments.test.js b/app/comments.test.js
index ddcc817..319c55e 100644
--- a/app/comments.test.js
+++ b/app/comments.test.js
@@ -6,13 +6,6 @@ import path from 'node:path';
 import { saveFindings, parseLocation, postNewCriticalComments, postFindingsReview } from './comments.js';
 import { FINDINGS_PATH } from './config.js';
 
-const REVIEW_SEVERITY_PATTERN = /\*\*嚴重等級\*\*：(🔴 嚴重|🟡 警告|🔵 建議)(?:\n|$)/;
-const REVIEW_SEVERITY_LABELS = ['🔴 嚴重', '🟡 警告', '🔵 建議'];
-
-function reviewSeverityLabel(comment) {
-  return comment.body.match(REVIEW_SEVERITY_PATTERN)?.[1];
-}
-
 describe('saveFindings', () => {
   const tempDirs = [];
   const makeTempDir = prefix => {
@@ -194,6 +187,21 @@ describe('postNewCriticalComments', () => {
 });
 
 describe('postFindingsReview', () => {
+  const REVIEW_SEVERITY_LABELS = ['🔴 嚴重', '🟡 警告', '🔵 建議'];
+  const REVIEW_SEVERITY_PATTERN = new RegExp(`\\*\\*嚴重等級\\*\\*：(${REVIEW_SEVERITY_LABELS.join('|')})(?:\\n|$)`);
+
+  function reviewSeverityLabel(comment) {
+    return comment?.body?.match(REVIEW_SEVERITY_PATTERN)?.[1];
+  }
+
+  it('handles missing review severity bodies gracefully', () => {
+    assert.equal(reviewSeverityLabel(null), undefined);
+    assert.equal(reviewSeverityLabel(undefined), undefined);
+    assert.equal(reviewSeverityLabel({}), undefined);
+    assert.equal(reviewSeverityLabel({ body: null }), undefined);
+    assert.equal(reviewSeverityLabel({ body: undefined }), undefined);
+  });
+
   it('extracts review severity labels only when the format is valid', () => {
     assert.equal(
       reviewSeverityLabel({ body: '**嚴重等級**：🔴 嚴重\n**審查員**：Rex' }),