diff --git a/tests/test_mingle_readings.py b/tests/test_mingle_readings.py
index 12234ba..92b341a 100644
--- a/tests/test_mingle_readings.py
+++ b/tests/test_mingle_readings.py
@@ -59,3 +59,4 @@ def test_split_possible_furigana() -> None:
     assert split_possible_furigana("明後日[あさって]") == WordReading("明後日", "あさって")
     assert split_possible_furigana("明後日[zzz]") == WordReading("明後日", "")
     assert split_possible_furigana("お 金[かね]") == WordReading("お金", "おかね")
+    assert split_possible_furigana("日") == WordReading("日", "")