diff --git a/unittest/formats/test_file_operations.cpp b/unittest/formats/test_file_operations.cpp
index 48d043b824..b5fd6af7d5 100644
--- a/unittest/formats/test_file_operations.cpp
+++ b/unittest/formats/test_file_operations.cpp
@@ -245,16 +245,17 @@ TEST_F(FileOperationsTest, logmesg)
     command("log test_logmesg.log");
     utils::logmesg(lmp, "two\n");
     utils::logmesg(lmp, "three={}\n", 3);
-    utils::logmesg(lmp, "four {}\n");
+    utils::logmesg(lmp, "four {} {}\n", 4);
     utils::logmesg(lmp, "five\n", 5);
+    utils::logmesg(lmp, "six {}\n");
     command("log none");
     std::string out = END_CAPTURE_OUTPUT();
     memset(buf, 0, 64);
     FILE *fp = fopen("test_logmesg.log", "r");
     fread(buf, 1, 64, fp);
     fclose(fp);
-    ASSERT_THAT(out, StrEq("one\ntwo\nthree=3\nargument not found\nfive\n"));
-    ASSERT_THAT(buf, StrEq("two\nthree=3\nargument not found\nfive\n"));
+    ASSERT_THAT(out, StrEq("one\ntwo\nthree=3\nargument not found\nfive\nsix {}\n"));
+    ASSERT_THAT(buf, StrEq("two\nthree=3\nargument not found\nfive\nsix {}\n"));
     remove("test_logmesg.log");
 }