diff --git a/src/core/wee-debug.c b/src/core/wee-debug.c
index 88233ccad..00655a448 100644
--- a/src/core/wee-debug.c
+++ b/src/core/wee-debug.c
@@ -736,29 +736,29 @@ debug_display_time_elapsed (struct timeval *time1, struct timeval *time2,
                             const char *message, int display)
 {
     struct timeval debug_timeval_end;
-    long long diff, diff_hour, diff_min, diff_sec, diff_usec;
+    char *str_diff;
+    long long diff;
 
     gettimeofday (&debug_timeval_end, NULL);
     diff = util_timeval_diff (time1, time2);
-
-    diff_usec = diff % 1000000;
-    diff_sec = (diff / 1000000) % 60;
-    diff_min = ((diff / 1000000) / 60) % 60;
-    diff_hour = (diff / 1000000) / 3600;
+    str_diff = util_get_microseconds_string (diff);
 
     if (display)
     {
         gui_chat_printf (NULL,
-                         "debug: time[%s] -> %lld:%02lld:%02lld.%06lld",
+                         "debug: time[%s] -> %s",
                          (message) ? message : "?",
-                         diff_hour, diff_min, diff_sec, diff_usec);
+                         (str_diff) ? str_diff : "?");
     }
     else
     {
-        log_printf ("debug: time[%s] -> %lld:%02lld:%02lld.%06lld",
+        log_printf ("debug: time[%s] -> %s",
                     (message) ? message : "?",
-                    diff_hour, diff_min, diff_sec, diff_usec);
+                    (str_diff) ? str_diff : "?");
     }
+
+    if (str_diff)
+        free (str_diff);
 }
 
 /*
diff --git a/src/core/wee-util.c b/src/core/wee-util.c
index 0e70aee4a..e39aa01bd 100644
--- a/src/core/wee-util.c
+++ b/src/core/wee-util.c
@@ -285,6 +285,31 @@ util_timeval_add (struct timeval *tv, long long interval)
         tv->tv_usec = usec;
 }
 
+/*
+ * Converts microseconds to a string, using format: "H:MM:SS.mmmmmm"
+ * where: H=hours, MM=minutes, SS=seconds, mmmmmm=microseconds
+ *
+ * Note: result must be freed after use.
+ */
+
+char *
+util_get_microseconds_string (long long microseconds)
+{
+    long long hour, min, sec, usec;
+    char result[128];
+
+    usec = microseconds % 1000000;
+    sec = (microseconds / 1000000) % 60;
+    min = ((microseconds / 1000000) / 60) % 60;
+    hour = (microseconds / 1000000) / 3600;
+
+    snprintf (result, sizeof (result),
+              "%lld:%02lld:%02lld.%06lld",
+              hour, min, sec, usec);
+
+    return strdup (result);
+}
+
 /*
  * Converts date to a string, using format of option "weechat.look.time_format"
  * (can be localized).
diff --git a/src/core/wee-util.h b/src/core/wee-util.h
index 1acb9a76d..d569e0c43 100644
--- a/src/core/wee-util.h
+++ b/src/core/wee-util.h
@@ -40,6 +40,7 @@ extern long long util_timeval_diff (struct timeval *tv1, struct timeval *tv2);
 extern void util_timeval_add (struct timeval *tv, long long interval);
 
 /* time */
+extern char *util_get_microseconds_string (long long diff);
 extern const char *util_get_time_string (const time_t *date);
 extern void util_get_time_diff (time_t time1, time_t time2,
                                 time_t *total_seconds,
diff --git a/tests/unit/core/test-core-util.cpp b/tests/unit/core/test-core-util.cpp
index 04aaa0554..e5021db53 100644
--- a/tests/unit/core/test-core-util.cpp
+++ b/tests/unit/core/test-core-util.cpp
@@ -21,6 +21,8 @@
 
 #include "CppUTest/TestHarness.h"
 
+#include "tests/tests.h"
+
 extern "C"
 {
 #include <unistd.h>
@@ -35,6 +37,26 @@ TEST_GROUP(CoreUtil)
 {
 };
 
+/*
+ * Tests functions:
+ *   util_setrlimit_resource
+ */
+
+TEST(CoreUtil, SetrlimitResource)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   util_setrlimit
+ */
+
+TEST(CoreUtil, Setrlimit)
+{
+    /* TODO: write tests */
+}
+
 /*
  * Tests functions:
  *   util_timeval_cmp
@@ -86,6 +108,43 @@ TEST(CoreUtil, Timeval)
     LONGS_EQUAL(21000, tv.tv_usec);
 }
 
+/*
+ * Tests functions:
+ *   util_get_microseconds_string
+ */
+
+TEST(CoreUtil, GetMicrosecondsString)
+{
+    char *str;
+
+    /* zero */
+    WEE_TEST_STR("0:00:00.000000",
+                 util_get_microseconds_string (0LL));
+
+    /* microseconds */
+    WEE_TEST_STR("0:00:00.000001", util_get_microseconds_string (1LL));
+    WEE_TEST_STR("0:00:00.000123", util_get_microseconds_string (123LL));
+
+    /* microseconds */
+    WEE_TEST_STR("0:00:00.001000", util_get_microseconds_string (1LL * 1000LL));
+    WEE_TEST_STR("0:00:00.123000", util_get_microseconds_string (123LL * 1000LL));
+
+    /* seconds */
+    WEE_TEST_STR("0:00:01.000000", util_get_microseconds_string (1LL * 1000LL * 1000LL));
+    WEE_TEST_STR("0:00:12.000000", util_get_microseconds_string (12LL * 1000LL * 1000LL));
+
+    /* minutes */
+    WEE_TEST_STR("0:01:00.000000", util_get_microseconds_string (1LL * 60LL * 1000LL * 1000LL));
+    WEE_TEST_STR("0:34:00.000000", util_get_microseconds_string (34LL * 60LL * 1000LL * 1000LL));
+
+    /* hours */
+    WEE_TEST_STR("1:00:00.000000", util_get_microseconds_string (1LL * 60LL * 60LL * 1000LL * 1000LL));
+    WEE_TEST_STR("34:00:00.000000", util_get_microseconds_string (34LL * 60LL * 60LL * 1000LL * 1000LL));
+
+    /* hours + minutes + seconds + milliseconds + microseconds */
+    WEE_TEST_STR("3:25:45.678901", util_get_microseconds_string (12345678901LL));
+}
+
 /*
  * Tests functions:
  *   util_get_time_string