diff --git a/src/test/util_string_tests.cpp b/src/test/util_string_tests.cpp
index fe3941b48f211e..002a13c7cd2a6d 100644
--- a/src/test/util_string_tests.cpp
+++ b/src/test/util_string_tests.cpp
@@ -42,6 +42,7 @@ BOOST_AUTO_TEST_CASE(ConstevalFormatString_NumSpec)
     PassFmt<0>("");
     PassFmt<0>("%%");
     PassFmt<1>("%s");
+    PassFmt<1>("%c");
     PassFmt<0>("%%s");
     PassFmt<0>("s%%");
     PassFmt<1>("%%%s");