diff --git a/tests/unit/test-cutils.c b/tests/unit/test-cutils.c
index f5b780f012..86caddcf64 100644
--- a/tests/unit/test-cutils.c
+++ b/tests/unit/test-cutils.c
@@ -2452,18 +2452,44 @@ static void test_qemu_strtosz_metric(void)
 
 static void test_freq_to_str(void)
 {
-    g_assert_cmpstr(freq_to_str(999), ==, "999 Hz");
-    g_assert_cmpstr(freq_to_str(1000), ==, "1 KHz");
-    g_assert_cmpstr(freq_to_str(1010), ==, "1.01 KHz");
+    char *str;
+
+    str = freq_to_str(999);
+    g_assert_cmpstr(str, ==, "999 Hz");
+    g_free(str);
+
+    str = freq_to_str(1000);
+    g_assert_cmpstr(str, ==, "1 KHz");
+    g_free(str);
+
+    str = freq_to_str(1010);
+    g_assert_cmpstr(str, ==, "1.01 KHz");
+    g_free(str);
 }
 
 static void test_size_to_str(void)
 {
-    g_assert_cmpstr(size_to_str(0), ==, "0 B");
-    g_assert_cmpstr(size_to_str(1), ==, "1 B");
-    g_assert_cmpstr(size_to_str(1016), ==, "0.992 KiB");
-    g_assert_cmpstr(size_to_str(1024), ==, "1 KiB");
-    g_assert_cmpstr(size_to_str(512ull << 20), ==, "512 MiB");
+    char *str;
+
+    str = size_to_str(0);
+    g_assert_cmpstr(str, ==, "0 B");
+    g_free(str);
+
+    str = size_to_str(1);
+    g_assert_cmpstr(str, ==, "1 B");
+    g_free(str);
+
+    str = size_to_str(1016);
+    g_assert_cmpstr(str, ==, "0.992 KiB");
+    g_free(str);
+
+    str = size_to_str(1024);
+    g_assert_cmpstr(str, ==, "1 KiB");
+    g_free(str);
+
+    str = size_to_str(512ull << 20);
+    g_assert_cmpstr(str, ==, "512 MiB");
+    g_free(str);
 }
 
 static void test_iec_binary_prefix(void)