Update test/test.cc

Co-authored-by: Copilot <[email protected]>

Author: yhirose

test/test.cc

@@ -12715,6 +12715,7 @@ TEST(ETagTest, StaticFileETagAndIfNoneMatch) {
   EXPECT_FALSE(etag.empty());
 
   // Verify ETag format: W/"hex-hex"
+  ASSERT_GE(etag.length(), 3u);
   EXPECT_EQ('W', etag[0]);
   EXPECT_EQ('/', etag[1]);
   EXPECT_EQ('"', etag[2]);