diff --git a/lib/isc/tests/Kyuafile b/lib/isc/tests/Kyuafile
index 1148f76f5c..8adf7ed51c 100644
--- a/lib/isc/tests/Kyuafile
+++ b/lib/isc/tests/Kyuafile
@@ -20,7 +20,7 @@ atf_test_program{name='queue_test'}
 tap_test_program{name='radix_test'}
 atf_test_program{name='regex_test'}
 tap_test_program{name='result_test'}
-atf_test_program{name='safe_test'}
+tap_test_program{name='safe_test'}
 atf_test_program{name='sockaddr_test'}
 atf_test_program{name='socket_test'}
 atf_test_program{name='symtab_test'}
diff --git a/lib/isc/tests/Makefile.in b/lib/isc/tests/Makefile.in
index e3fd51825a..0fb8eb8ba7 100644
--- a/lib/isc/tests/Makefile.in
+++ b/lib/isc/tests/Makefile.in
@@ -145,8 +145,9 @@ result_test@EXEEXT@: result_test.@O@ ${ISCDEPLIBS}
 		${ISCLIBS} ${LIBS} ${CMOCKA_LIBS}
 
 safe_test@EXEEXT@: safe_test.@O@ ${ISCDEPLIBS}
-	${LIBTOOL_MODE_LINK} ${PURIFY} ${CC} ${CFLAGS} ${LDFLAGS} -o $@ \
-			safe_test.@O@ ${ISCLIBS} ${LIBS}
+	${LIBTOOL_MODE_LINK} ${PURIFY} ${CC} ${CFLAGS} ${CMOCKA_CFLAGS} \
+		${LDFLAGS} -o $@ safe_test.@O@ \
+		${ISCLIBS} ${LIBS} ${CMOCKA_LIBS}
 
 socket_test@EXEEXT@: socket_test.@O@ isctest.@O@ ${ISCDEPLIBS}
 	${LIBTOOL_MODE_LINK} ${PURIFY} ${CC} ${CFLAGS} ${LDFLAGS} -o $@ \
diff --git a/lib/isc/tests/safe_test.c b/lib/isc/tests/safe_test.c
index ea3e61f98d..af1d377c70 100644
--- a/lib/isc/tests/safe_test.c
+++ b/lib/isc/tests/safe_test.c
@@ -9,42 +9,44 @@
  * information regarding copyright ownership.
  */
 
-
 /* ! \file */
 
 #include <config.h>
 
-#include <atf-c.h>
+#if HAVE_CMOCKA
+
+#include <stdarg.h>
+#include <stddef.h>
+#include <setjmp.h>
 
-#include <stdio.h>
 #include <string.h>
+#include <stdlib.h>
+
+#define UNIT_TESTING
+#include <cmocka.h>
 
 #include <isc/safe.h>
 #include <isc/util.h>
 
-ATF_TC(isc_safe_memequal);
-ATF_TC_HEAD(isc_safe_memequal, tc) {
-	atf_tc_set_md_var(tc, "descr", "safe memequal()");
-}
-ATF_TC_BODY(isc_safe_memequal, tc) {
-	UNUSED(tc);
+/* test isc_safe_memequal() */
+static void
+isc_safe_memequal_test(void **state) {
+	UNUSED(state);
 
-	ATF_CHECK(isc_safe_memequal("test", "test", 4));
-	ATF_CHECK(!isc_safe_memequal("test", "tesc", 4));
-	ATF_CHECK(isc_safe_memequal("\x00\x00\x00\x00",
-				    "\x00\x00\x00\x00", 4));
-	ATF_CHECK(!isc_safe_memequal("\x00\x00\x00\x00",
-				     "\x00\x00\x00\x01", 4));
-	ATF_CHECK(!isc_safe_memequal("\x00\x00\x00\x02",
-				     "\x00\x00\x00\x00", 4));
+	assert_true(isc_safe_memequal("test", "test", 4));
+	assert_true(!isc_safe_memequal("test", "tesc", 4));
+	assert_true(isc_safe_memequal("\x00\x00\x00\x00",
+				      "\x00\x00\x00\x00", 4));
+	assert_true(!isc_safe_memequal("\x00\x00\x00\x00",
+				       "\x00\x00\x00\x01", 4));
+	assert_true(!isc_safe_memequal("\x00\x00\x00\x02",
+				       "\x00\x00\x00\x00", 4));
 }
 
-ATF_TC(isc_safe_memwipe);
-ATF_TC_HEAD(isc_safe_memwipe, tc) {
-	atf_tc_set_md_var(tc, "descr", "isc_safe_memwipe()");
-}
-ATF_TC_BODY(isc_safe_memwipe, tc) {
-	UNUSED(tc);
+/* test isc_safe_memwipe() */
+static void
+isc_safe_memwipe_test(void **state) {
+	UNUSED(state);
 
 	/* These should pass. */
 	isc_safe_memwipe(NULL, 0);
@@ -61,7 +63,7 @@ ATF_TC_BODY(isc_safe_memwipe, tc) {
 		isc_safe_memwipe(buf1, sizeof(buf1));
 		memset(buf2, 0, sizeof(buf2));
 
-		ATF_CHECK(memcmp(buf1, buf2, sizeof(buf1)) == 0);
+		assert_int_equal(memcmp(buf1, buf2, sizeof(buf1)), 0);
 	}
 
 	/*
@@ -78,15 +80,28 @@ ATF_TC_BODY(isc_safe_memwipe, tc) {
 		isc_safe_memwipe(buf1, 3);
 		memset(buf2, 0, 3);
 
-		ATF_CHECK(memcmp(buf1, buf2, sizeof(buf1)) == 0);
+		assert_int_equal(memcmp(buf1, buf2, sizeof(buf1)), 0);
 	}
 }
 
-/*
- * Main
- */
-ATF_TP_ADD_TCS(tp) {
-	ATF_TP_ADD_TC(tp, isc_safe_memequal);
-	ATF_TP_ADD_TC(tp, isc_safe_memwipe);
-	return (atf_no_error());
+int
+main(void) {
+	const struct CMUnitTest tests[] = {
+		cmocka_unit_test(isc_safe_memequal_test),
+		cmocka_unit_test(isc_safe_memwipe_test),
+	};
+
+	return (cmocka_run_group_tests(tests, NULL, NULL));
 }
+
+#else /* HAVE_CMOCKA */
+
+#include <stdio.h>
+
+int
+main(void) {
+	printf("1..0 # Skipped: cmocka not available\n");
+	return (0);
+}
+
+#endif