test: Add timer test

Verify the existing usleep() function in preparation for moving its
implementation into the builtin folder.

BUG=b:260723169
TEST=test/run_device_tests.py -b bloonchipper -t timer
TEST=test/run_device_tests.py -b dartmonkey -t timer
TEST=make run-timer
BRANCH=none

Change-Id: I532fa5ac7abf7b16b4d1a86ea5e961f08fb2f1b7
Signed-off-by: Andrea Grandi <agrandi@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/4068487
Code-Coverage: Zoss <zoss-cl-coverage@prod.google.com>
Reviewed-by: Tom Hughes <tomhughes@chromium.org>

1 files changed, 42 insertions, 0 deletions

diff --git a/test/timer.cc b/test/timer.cc
new file mode 100644
index 0000000000..8eb5f87519
--- /dev/null
+++ b/test/timer.cc
@@ -0,0 +1,42 @@
+/* Copyright 2022 The ChromiumOS Authors
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/** @brief Test functions defined in timer.h, like usleep().
+ *
+ * This test only validates the functionality of code in timer.h and is not
+ * expected to accurately measure/check the timing.
+ */
+
+#include "common.h"
+#include "math_util.h"
+#include "test_util.h"
+
+extern "C" {
+#include "timer.h"
+#include "watchdog.h"
+}
+
+test_static int test_usleep(void)
+{
+	constexpr int expected_duration = 12345;
+
+	timestamp_t start_time = get_time();
+	usleep(expected_duration);
+	int sleep_duration = time_since32(start_time);
+
+	TEST_NEAR(expected_duration, sleep_duration, 20, "%d");
+
+	return EC_SUCCESS;
+}
+
+void run_test(int argc, const char **argv)
+{
+	test_reset();
+	watchdog_reload();
+
+	RUN_TEST(test_usleep);
+
+	test_print_result();
+}