diff --git a/tests/signal_test.cpp b/tests/signal_test.cpp
index 1ae174a..6db7751 100644
--- a/tests/signal_test.cpp
+++ b/tests/signal_test.cpp
@@ -20,6 +20,7 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+#include <chrono>
 #include <thread>
 
 #include <android-base/macros.h>
@@ -27,6 +28,8 @@
 
 #include "SignalUtils.h"
 
+using namespace std::chrono_literals;
+
 static int SIGNAL_MIN() {
   return 1; // Signals start at 1 (SIGHUP), not 0.
 }
@@ -753,12 +756,6 @@
   ASSERT_EQ(0, errno);
 }
 
-static int64_t NanoTime() {
-  timespec t;
-  clock_gettime(CLOCK_MONOTONIC, &t);
-  return static_cast<int64_t>(t.tv_sec) * 1000000000LL + t.tv_nsec;
-}
-
 TEST(signal, sigtimedwait_timeout) {
   // Block SIGALRM.
   sigset_t just_SIGALRM;
@@ -768,13 +765,14 @@
   ASSERT_EQ(0, sigprocmask(SIG_BLOCK, &just_SIGALRM, &original_set));
 
   // Wait timeout.
-  int64_t start_time = NanoTime();
+  auto t0 = std::chrono::steady_clock::now();
   siginfo_t info;
   timespec timeout = { .tv_sec = 0, .tv_nsec = 1000000 };
   errno = 0;
   ASSERT_EQ(-1, sigtimedwait(&just_SIGALRM, &info, &timeout));
   ASSERT_EQ(EAGAIN, errno);
-  ASSERT_GE(NanoTime() - start_time, 1000000);
+  auto t1 = std::chrono::steady_clock::now();
+  ASSERT_GE(t1-t0, 1000000ns);
 
   ASSERT_EQ(0, sigprocmask(SIG_SETMASK, &original_set, nullptr));
 }
diff --git a/tests/system_properties_test2.cpp b/tests/system_properties_test2.cpp
index c061faa..b9936dd 100644
--- a/tests/system_properties_test2.cpp
+++ b/tests/system_properties_test2.cpp
@@ -19,16 +19,16 @@
 #include <errno.h>
 #include <sys/wait.h>
 #include <unistd.h>
+
+#include <chrono>
 #include <sstream>
 #include <string>
 
 #if defined(__BIONIC__)
 #include <sys/system_properties.h>
-
-static uint64_t NanoTime() {
-  timespec now;
-  clock_gettime(CLOCK_MONOTONIC, &now);
-  return static_cast<uint64_t>(now.tv_sec) * UINT64_C(1000000000) + now.tv_nsec;
+int64_t NanoTime() {
+  auto t = std::chrono::time_point_cast<std::chrono::nanoseconds>(std::chrono::steady_clock::now());
+  return t.time_since_epoch().count();
 }
 #endif
 
diff --git a/tests/time_test.cpp b/tests/time_test.cpp
index 4e17242..378b4ac 100644
--- a/tests/time_test.cpp
+++ b/tests/time_test.cpp
@@ -24,13 +24,17 @@
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <unistd.h>
+
 #include <atomic>
+#include <chrono>
 
 #include "SignalUtils.h"
 #include "utils.h"
 
 #include "private/bionic_constants.h"
 
+using namespace std::chrono_literals;
+
 TEST(time, time) {
   // Acquire time
   time_t p1, t1 = time(&p1);
@@ -797,7 +801,7 @@
   ASSERT_EQ(EINVAL, errno);
 }
 
-TEST(time, clock_nanosleep) {
+TEST(time, clock_nanosleep_EINVAL) {
   timespec in;
   timespec out;
   ASSERT_EQ(EINVAL, clock_nanosleep(-1, 0, &in, &out));
@@ -810,6 +814,29 @@
   ASSERT_EQ(EINVAL, clock_nanosleep(CLOCK_THREAD_CPUTIME_ID, 0, &in, nullptr));
 }
 
+TEST(time, clock_nanosleep) {
+  auto t0 = std::chrono::steady_clock::now();
+  const timespec ts = {.tv_nsec = 5000000};
+  ASSERT_EQ(0, clock_nanosleep(CLOCK_MONOTONIC, 0, &ts, nullptr));
+  auto t1 = std::chrono::steady_clock::now();
+  ASSERT_GE(t1-t0, 5000000ns);
+}
+
+TEST(time, nanosleep) {
+  auto t0 = std::chrono::steady_clock::now();
+  const timespec ts = {.tv_nsec = 5000000};
+  ASSERT_EQ(0, nanosleep(&ts, nullptr));
+  auto t1 = std::chrono::steady_clock::now();
+  ASSERT_GE(t1-t0, 5000000ns);
+}
+
+TEST(time, nanosleep_EINVAL) {
+  timespec ts = {.tv_sec = -1};
+  errno = 0;
+  ASSERT_EQ(-1, nanosleep(&ts, nullptr));
+  ASSERT_EQ(EINVAL, errno);
+}
+
 TEST(time, bug_31938693) {
   // User-visible symptoms in N:
   // http://b/31938693
diff --git a/tests/unistd_test.cpp b/tests/unistd_test.cpp
index 10c1710..99d92e6 100644
--- a/tests/unistd_test.cpp
+++ b/tests/unistd_test.cpp
@@ -33,6 +33,8 @@
 #include <sys/wait.h>
 #include <unistd.h>
 
+#include <chrono>
+
 #include <android-base/file.h>
 #include <android-base/strings.h>
 
@@ -46,6 +48,8 @@
 #define UNISTD_DEATHTEST unistd_DeathTest
 #endif
 
+using namespace std::chrono_literals;
+
 static void* get_brk() {
   return sbrk(0);
 }
@@ -1516,3 +1520,17 @@
   swab("hello", buf, -1);
   ASSERT_EQ('x', buf[0]);
 }
+
+TEST(UNISTD_TEST, usleep) {
+  auto t0 = std::chrono::steady_clock::now();
+  ASSERT_EQ(0, usleep(5000));
+  auto t1 = std::chrono::steady_clock::now();
+  ASSERT_GE(t1-t0, 5000us);
+}
+
+TEST(UNISTD_TEST, sleep) {
+  auto t0 = std::chrono::steady_clock::now();
+  ASSERT_EQ(0U, sleep(1));
+  auto t1 = std::chrono::steady_clock::now();
+  ASSERT_GE(t1-t0, 1s);
+}
diff --git a/tests/utils.h b/tests/utils.h
index fe41019..1f4cece 100644
--- a/tests/utils.h
+++ b/tests/utils.h
@@ -14,8 +14,7 @@
  * limitations under the License.
  */
 
-#ifndef __TEST_UTILS_H
-#define __TEST_UTILS_H
+#pragma once
 
 #include <dlfcn.h>
 #include <fcntl.h>
@@ -254,5 +253,3 @@
   std::string output_;
 };
 #endif
-
-#endif