diff --git a/utils/process/Kyuafile b/utils/process/Kyuafile
index 37ab6629..1eb47ef5 100644
--- a/utils/process/Kyuafile
+++ b/utils/process/Kyuafile
@@ -6,7 +6,7 @@ atf_test_program{name="child_test"}
 atf_test_program{name="deadline_killer_test"}
 atf_test_program{name="exceptions_test"}
 atf_test_program{name="executor_test"}
-atf_test_program{name="executor_pid_test"}
+atf_test_program{name="executor_pid_test", required_user="root"}
 atf_test_program{name="fdstream_test"}
 atf_test_program{name="isolation_test"}
 atf_test_program{name="operations_test"}
diff --git a/utils/process/Makefile.am.inc b/utils/process/Makefile.am.inc
index a0137075..31cd8db7 100644
--- a/utils/process/Makefile.am.inc
+++ b/utils/process/Makefile.am.inc
@@ -84,8 +84,8 @@ utils_process_executor_test_CXXFLAGS = $(UTILS_CFLAGS) $(ATF_CXX_CFLAGS)
 utils_process_executor_test_LDADD = $(UTILS_LIBS) $(ATF_CXX_LIBS)
 
 tests_utils_process_PROGRAMS += utils/process/executor_pid_test
-utils_process_executor_pid_test_SOURCES = utils/process/executor_pid_test.cpp
-utils_process_executor_pid_test_CXXFLAGS = $(UTILS_CFLAGS) $(ATF_CXX_CFLAGS)
+utils_process_executor_pid_test_SOURCES = utils/process/executor_pid_test.c
+utils_process_executor_pid_test_CFLAGS = $(UTILS_CFLAGS) $(ATF_CXX_CFLAGS)
 utils_process_executor_pid_test_LDADD = $(UTILS_LIBS) $(ATF_CXX_LIBS)
 
 tests_utils_process_PROGRAMS += utils/process/fdstream_test
diff --git a/utils/process/executor_pid_test.cpp b/utils/process/executor_pid_test.c
similarity index 57%
rename from utils/process/executor_pid_test.cpp
rename to utils/process/executor_pid_test.c
index 22e0b90b..17f9bc02 100644
--- a/utils/process/executor_pid_test.cpp
+++ b/utils/process/executor_pid_test.c
@@ -69,28 +69,33 @@ Abort trap (core dumped)
 
 #include <sys/stat.h>
 
-#include <atf-c++.hpp>
+#include <atf-c.h>
 
+#include <errno.h>
 #include <fcntl.h>
 #include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 #include <unistd.h>
 
-#include <cerrno>
-#include <cstring>
-
 void
-leak_work_dir()
+leak_work_dir(void)
 {
 	int fd;
 
-	ATF_REQUIRE((fd = open("unforgettable", O_CREAT|O_EXCL|O_WRONLY, 0600))
-	    >= 0);
-	ATF_REQUIRE_EQ(0, fchflags(fd, UF_NOUNLINK));
+	fd = open("unforgettable", O_CREAT|O_EXCL|O_WRONLY, 0600);
+	ATF_REQUIRE_MSG(fd != -1,
+	    "open(..., O_CREAT|O_EXCL|O_WRONLY, 0600) failed unexpectedly: %s",
+	    strerror(errno));
+	ATF_REQUIRE_EQ_MSG(0, fchflags(fd, SF_NOUNLINK),
+	    "fchflags(..., UF_NOUNLINK): failed unexpectedly: %s",
+	    strerror(errno));
 	ATF_REQUIRE_EQ(0, close(fd));
 }
 
 void
-wrap_pids()
+wrap_pids(void)
 {
 	pid_t begin, current, target;
 	bool wrapped;
@@ -119,90 +124,87 @@ wrap_pids()
 }
 
 void
-test_work_dir_reuse()
+test_work_dir_reuse(void)
 {
 	// If kyua is built with debugging, it would abort here before the fix.
 }
 
 void
-clean_up()
+clean_up(void)
+{
+	(void)system("chflags -R nosunlink ../..");
+}
+
+#define	LEAK_WORKDIR_TC(name) 		\
+	ATF_TC_WITHOUT_HEAD(name);	\
+	ATF_TC_BODY(name, tc) { 	\
+		leak_work_dir(); 	\
+	}
+
+LEAK_WORKDIR_TC(leak_0)
+LEAK_WORKDIR_TC(leak_1)
+LEAK_WORKDIR_TC(leak_2)
+LEAK_WORKDIR_TC(leak_3)
+LEAK_WORKDIR_TC(leak_4)
+LEAK_WORKDIR_TC(leak_5)
+LEAK_WORKDIR_TC(leak_6)
+LEAK_WORKDIR_TC(leak_7)
+LEAK_WORKDIR_TC(leak_8)
+LEAK_WORKDIR_TC(leak_9)
+
+ATF_TC_WITHOUT_HEAD(pid_wrap);
+ATF_TC_BODY(pid_wrap, tc) { wrap_pids(); }
+
+#define	PID_WRAP_TC(name) 		\
+	ATF_TC_WITHOUT_HEAD(name);	\
+	ATF_TC_BODY(name, tc) {		\
+		test_work_dir_reuse();	\
+	}
+
+PID_WRAP_TC(pid_wrap_0)
+PID_WRAP_TC(pid_wrap_1)
+PID_WRAP_TC(pid_wrap_2)
+PID_WRAP_TC(pid_wrap_3)
+PID_WRAP_TC(pid_wrap_4)
+PID_WRAP_TC(pid_wrap_5)
+PID_WRAP_TC(pid_wrap_6)
+PID_WRAP_TC(pid_wrap_7)
+PID_WRAP_TC(pid_wrap_8)
+PID_WRAP_TC(pid_wrap_9)
+
+ATF_TC_WITHOUT_HEAD(really_clean_up);
+ATF_TC_BODY(really_clean_up, tc)
 {
-	(void)system("chflags -R nouunlink ../..");
+	clean_up();
 }
 
-ATF_TEST_CASE_WITHOUT_HEAD(leak_0);
-ATF_TEST_CASE_BODY(leak_0) { leak_work_dir(); }
-ATF_TEST_CASE_WITHOUT_HEAD(leak_1);
-ATF_TEST_CASE_BODY(leak_1) { leak_work_dir(); }
-ATF_TEST_CASE_WITHOUT_HEAD(leak_2);
-ATF_TEST_CASE_BODY(leak_2) { leak_work_dir(); }
-ATF_TEST_CASE_WITHOUT_HEAD(leak_3);
-ATF_TEST_CASE_BODY(leak_3) { leak_work_dir(); }
-ATF_TEST_CASE_WITHOUT_HEAD(leak_4);
-ATF_TEST_CASE_BODY(leak_4) { leak_work_dir(); }
-ATF_TEST_CASE_WITHOUT_HEAD(leak_5);
-ATF_TEST_CASE_BODY(leak_5) { leak_work_dir(); }
-ATF_TEST_CASE_WITHOUT_HEAD(leak_6);
-ATF_TEST_CASE_BODY(leak_6) { leak_work_dir(); }
-ATF_TEST_CASE_WITHOUT_HEAD(leak_7);
-ATF_TEST_CASE_BODY(leak_7) { leak_work_dir(); }
-ATF_TEST_CASE_WITHOUT_HEAD(leak_8);
-ATF_TEST_CASE_BODY(leak_8) { leak_work_dir(); }
-ATF_TEST_CASE_WITHOUT_HEAD(leak_9);
-ATF_TEST_CASE_BODY(leak_9) { leak_work_dir(); }
-
-ATF_TEST_CASE_WITHOUT_HEAD(pid_wrap);
-ATF_TEST_CASE_BODY(pid_wrap) { wrap_pids(); }
-
-ATF_TEST_CASE_WITHOUT_HEAD(pid_wrap_0);
-ATF_TEST_CASE_BODY(pid_wrap_0) { test_work_dir_reuse(); }
-ATF_TEST_CASE_WITHOUT_HEAD(pid_wrap_1);
-ATF_TEST_CASE_BODY(pid_wrap_1) { test_work_dir_reuse(); }
-ATF_TEST_CASE_WITHOUT_HEAD(pid_wrap_2);
-ATF_TEST_CASE_BODY(pid_wrap_2) { test_work_dir_reuse(); }
-ATF_TEST_CASE_WITHOUT_HEAD(pid_wrap_3);
-ATF_TEST_CASE_BODY(pid_wrap_3) { test_work_dir_reuse(); }
-ATF_TEST_CASE_WITHOUT_HEAD(pid_wrap_4);
-ATF_TEST_CASE_BODY(pid_wrap_4) { test_work_dir_reuse(); }
-ATF_TEST_CASE_WITHOUT_HEAD(pid_wrap_5);
-ATF_TEST_CASE_BODY(pid_wrap_5) { test_work_dir_reuse(); }
-ATF_TEST_CASE_WITHOUT_HEAD(pid_wrap_6);
-ATF_TEST_CASE_BODY(pid_wrap_6) { test_work_dir_reuse(); }
-ATF_TEST_CASE_WITHOUT_HEAD(pid_wrap_7);
-ATF_TEST_CASE_BODY(pid_wrap_7) { test_work_dir_reuse(); }
-ATF_TEST_CASE_WITHOUT_HEAD(pid_wrap_8);
-ATF_TEST_CASE_BODY(pid_wrap_8) { test_work_dir_reuse(); }
-ATF_TEST_CASE_WITHOUT_HEAD(pid_wrap_9);
-ATF_TEST_CASE_BODY(pid_wrap_9) { test_work_dir_reuse(); }
-
-ATF_TEST_CASE_WITHOUT_HEAD(really_clean_up);
-ATF_TEST_CASE_BODY(really_clean_up) { clean_up(); }
-
-ATF_INIT_TEST_CASES(tcs)
+ATF_TP_ADD_TCS(tcs)
 {
-	ATF_ADD_TEST_CASE(tcs, leak_0);
-	ATF_ADD_TEST_CASE(tcs, leak_1);
-	ATF_ADD_TEST_CASE(tcs, leak_2);
-	ATF_ADD_TEST_CASE(tcs, leak_3);
-	ATF_ADD_TEST_CASE(tcs, leak_4);
-	ATF_ADD_TEST_CASE(tcs, leak_5);
-	ATF_ADD_TEST_CASE(tcs, leak_6);
-	ATF_ADD_TEST_CASE(tcs, leak_7);
-	ATF_ADD_TEST_CASE(tcs, leak_8);
-	ATF_ADD_TEST_CASE(tcs, leak_9);
-
-	ATF_ADD_TEST_CASE(tcs, pid_wrap);
-
-	ATF_ADD_TEST_CASE(tcs, pid_wrap_0);
-	ATF_ADD_TEST_CASE(tcs, pid_wrap_1);
-	ATF_ADD_TEST_CASE(tcs, pid_wrap_2);
-	ATF_ADD_TEST_CASE(tcs, pid_wrap_3);
-	ATF_ADD_TEST_CASE(tcs, pid_wrap_4);
-	ATF_ADD_TEST_CASE(tcs, pid_wrap_5);
-	ATF_ADD_TEST_CASE(tcs, pid_wrap_6);
-	ATF_ADD_TEST_CASE(tcs, pid_wrap_7);
-	ATF_ADD_TEST_CASE(tcs, pid_wrap_8);
-	ATF_ADD_TEST_CASE(tcs, pid_wrap_9);
-
-	ATF_ADD_TEST_CASE(tcs, really_clean_up);
+	ATF_TP_ADD_TC(tcs, leak_0);
+	ATF_TP_ADD_TC(tcs, leak_1);
+	ATF_TP_ADD_TC(tcs, leak_2);
+	ATF_TP_ADD_TC(tcs, leak_3);
+	ATF_TP_ADD_TC(tcs, leak_4);
+	ATF_TP_ADD_TC(tcs, leak_5);
+	ATF_TP_ADD_TC(tcs, leak_6);
+	ATF_TP_ADD_TC(tcs, leak_7);
+	ATF_TP_ADD_TC(tcs, leak_8);
+	ATF_TP_ADD_TC(tcs, leak_9);
+
+	ATF_TP_ADD_TC(tcs, pid_wrap);
+
+	ATF_TP_ADD_TC(tcs, pid_wrap_0);
+	ATF_TP_ADD_TC(tcs, pid_wrap_1);
+	ATF_TP_ADD_TC(tcs, pid_wrap_2);
+	ATF_TP_ADD_TC(tcs, pid_wrap_3);
+	ATF_TP_ADD_TC(tcs, pid_wrap_4);
+	ATF_TP_ADD_TC(tcs, pid_wrap_5);
+	ATF_TP_ADD_TC(tcs, pid_wrap_6);
+	ATF_TP_ADD_TC(tcs, pid_wrap_7);
+	ATF_TP_ADD_TC(tcs, pid_wrap_8);
+	ATF_TP_ADD_TC(tcs, pid_wrap_9);
+
+	ATF_TP_ADD_TC(tcs, really_clean_up);
+
+	return atf_no_error();
 }