diff --git a/packages/backend-rs/src/misc/check_word_mute.rs b/packages/backend-rs/src/misc/check_word_mute.rs
index 1abeeaf33c..aacb9e4a2f 100644
--- a/packages/backend-rs/src/misc/check_word_mute.rs
+++ b/packages/backend-rs/src/misc/check_word_mute.rs
@@ -42,3 +42,141 @@ pub async fn check_word_mute(
         ))
     }
 }
+
+#[cfg(test)]
+mod unit_test {
+    use super::check_word_mute_impl;
+
+    #[test]
+    fn test_word_mute_match() {
+        let texts = vec![
+            "The quick brown fox jumps over the lazy dog.".to_string(),
+            "色は匂へど 散りぬるを 我が世誰ぞ 常ならむ".to_string(),
+            "😇".to_string(),
+        ];
+
+        let hiragana_1 = r#"/[\u{3040}-\u{309f}]/u"#.to_string();
+        let hiragana_2 = r#"/[あ-ん]/u"#.to_string();
+        let katakana_1 = r#"/[\u{30a1}-\u{30ff}]/u"#.to_string();
+        let katakana_2 = r#"/[ア-ン]/u"#.to_string();
+        let emoji = r#"/[\u{1f300}-\u{1f5ff}\u{1f900}-\u{1f9ff}\u{1f600}-\u{1f64f}\u{1f680}-\u{1f6ff}\u{2600}-\u{26ff}\u{2700}-\u{27bf}\u{1f1e6}-\u{1f1ff}\u{1f191}-\u{1f251}\u{1f004}\u{1f0cf}\u{1f170}-\u{1f171}\u{1f17e}-\u{1f17f}\u{1f18e}\u{3030}\u{2b50}\u{2b55}\u{2934}-\u{2935}\u{2b05}-\u{2b07}\u{2b1b}-\u{2b1c}\u{3297}\u{3299}\u{303d}\u{00a9}\u{00ae}\u{2122}\u{23f3}\u{24c2}\u{23e9}-\u{23ef}\u{25b6}\u{23f8}-\u{23fa}]/u"#.to_string();
+
+        assert!(check_word_mute_impl(
+            &texts,
+            &vec![],
+            &vec!["/the/i".to_string()]
+        ));
+
+        assert!(!check_word_mute_impl(
+            &texts,
+            &vec![],
+            &vec!["/the/".to_string()]
+        ));
+
+        assert!(check_word_mute_impl(
+            &texts,
+            &vec![],
+            &vec!["/QuICk/i".to_string()]
+        ));
+
+        assert!(!check_word_mute_impl(
+            &texts,
+            &vec![],
+            &vec!["/QuICk/".to_string()]
+        ));
+
+        assert!(check_word_mute_impl(
+            &texts,
+            &vec![
+                "我".to_string(),
+                "有為の奥山 今日越えて 浅き夢見し 酔ひもせず".to_string()
+            ],
+            &vec![]
+        ));
+
+        assert!(!check_word_mute_impl(
+            &texts,
+            &vec!["有為の奥山 今日越えて 浅き夢見し 酔ひもせず".to_string()],
+            &vec![]
+        ));
+
+        assert!(!check_word_mute_impl(
+            &texts,
+            &vec![
+                "有為の奥山".to_string(),
+                "今日越えて".to_string(),
+                "浅き夢見し".to_string(),
+                "酔ひもせず".to_string()
+            ],
+            &vec![]
+        ));
+
+        assert!(check_word_mute_impl(
+            &texts,
+            &vec!["yellow fox".to_string(), "mastodon".to_string()],
+            &vec![hiragana_1.clone()]
+        ));
+
+        assert!(check_word_mute_impl(
+            &texts,
+            &vec!["yellow fox".to_string(), "mastodon".to_string()],
+            &vec![hiragana_2.clone()]
+        ));
+
+        assert!(!check_word_mute_impl(
+            &texts,
+            &vec!["yellow fox".to_string(), "mastodon".to_string()],
+            &vec![katakana_1.clone()]
+        ));
+
+        assert!(!check_word_mute_impl(
+            &texts,
+            &vec!["yellow fox".to_string(), "mastodon".to_string()],
+            &vec![katakana_2.clone()]
+        ));
+
+        assert!(check_word_mute_impl(
+            &texts,
+            &vec!["brown fox".to_string(), "mastodon".to_string()],
+            &vec![katakana_1.clone()]
+        ));
+
+        assert!(check_word_mute_impl(
+            &texts,
+            &vec!["brown fox".to_string(), "mastodon".to_string()],
+            &vec![katakana_2.clone()]
+        ));
+
+        assert!(check_word_mute_impl(
+            &texts,
+            &vec!["yellow fox".to_string(), "dog".to_string()],
+            &vec![katakana_1.clone()]
+        ));
+
+        assert!(check_word_mute_impl(
+            &texts,
+            &vec!["yellow fox".to_string(), "dog".to_string()],
+            &vec![katakana_2.clone()]
+        ));
+
+        assert!(check_word_mute_impl(
+            &texts,
+            &vec!["yellow fox".to_string(), "mastodon".to_string()],
+            &vec![hiragana_1.clone(), katakana_1.clone()]
+        ));
+
+        assert!(check_word_mute_impl(
+            &texts,
+            &vec!["😇".to_string(), "🥲".to_string(), "🥴".to_string()],
+            &vec![]
+        ));
+
+        assert!(!check_word_mute_impl(
+            &texts,
+            &vec!["🙂".to_string(), "🥲".to_string(), "🥴".to_string()],
+            &vec![]
+        ));
+
+        assert!(check_word_mute_impl(&texts, &vec![], &vec![emoji.clone()]));
+    }
+}