diff --git a/t/unit/core/time_test.c b/t/unit/core/time_test.c
--- /dev/null
+++ b/t/unit/core/time_test.c
@@ -0,0 +1,99 @@
+/*
+ * SysDB - t/unit/core/time_test.c
+ * Copyright (C) 2014 Sebastian 'tokkee' Harl <sh@tokkee.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "core/time.h"
+#include "libsysdb_test.h"
+
+#include <check.h>
+
+START_TEST(test_strfinterval)
+{
+ char buf[1024];
+ size_t check;
+ size_t i;
+
+ struct {
+ sdb_time_t interval;
+ const char *expected;
+ } golden_data[] = {
+ { 0, "0s" },
+ { 4711, ".000004711s" },
+ { 1000123400, "1.0001234s" },
+ { 47940228000000000L, "1Y6M7D" },
+ { SDB_INTERVAL_YEAR, "1Y" },
+ { SDB_INTERVAL_MONTH, "1M" },
+ { SDB_INTERVAL_DAY, "1D" },
+ { SDB_INTERVAL_HOUR, "1h" },
+ { SDB_INTERVAL_MINUTE, "1m" },
+ { SDB_INTERVAL_SECOND, "1s" },
+ { SDB_INTERVAL_YEAR
+ + SDB_INTERVAL_MONTH
+ + SDB_INTERVAL_DAY
+ + SDB_INTERVAL_HOUR
+ + SDB_INTERVAL_MINUTE
+ + SDB_INTERVAL_SECOND
+ + 1234, "1Y1M1D1h1m1.000001234s" },
+ };
+
+ /* this should return the number of bytes which would have been written;
+ * most notably, it should not segfault ;-) */
+ check = sdb_strfinterval(NULL, 0, 4711); /* expected: .000004711s */
+ fail_unless(check == 11,
+ "sdb_strfinterval(NULL, 0, 4711) = %zu; expected: 11", check);
+
+ for (i = 0; i < SDB_STATIC_ARRAY_LEN(golden_data); ++i) {
+ check = sdb_strfinterval(buf, sizeof(buf), golden_data[i].interval);
+ fail_unless(check > 0,
+ "sdb_strfinterval(<buf>, <size>, %"PRIscTIME") = %zu; "
+ "expected: >0", golden_data[i].interval, check);
+ fail_unless(!strcmp(buf, golden_data[i].expected),
+ "sdb_strfinterval(<buf>, <size>, %"PRIscTIME") did not "
+ "format interval correctly; got: '%s'; expected: '%s'",
+ golden_data[i].interval, buf, golden_data[i].expected);
+ fail_unless(check == strlen(golden_data[i].expected),
+ "sdb_strfinterval(<buf>, <size>, %"PRIscTIME") = %zu; "
+ "expected: %zu", golden_data[i].interval, check,
+ strlen(golden_data[i].expected));
+ }
+}
+END_TEST
+
+Suite *
+core_time_suite(void)
+{
+ Suite *s = suite_create("core::time");
+ TCase *tc;
+
+ tc = tcase_create("core");
+ tcase_add_test(tc, test_strfinterval);
+ suite_add_tcase(s, tc);
+
+ return s;
+} /* core_time_suite */
+
+/* vim: set tw=78 sw=4 ts=4 noexpandtab : */
+