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#include "gtest/gtest.h"
#include "serial/impl/unix.h"
#include <unistd.h>
#include <stdlib.h>
using serial::MillisecondTimer;
namespace {
/**
* Do 100 trials of timing gaps between 0 and 19 milliseconds.
* Expect accuracy within one millisecond.
*/
TEST(timer_tests, short_intervals) {
for (int trial = 0; trial < 100; trial++)
{
uint32_t ms = rand() % 20;
MillisecondTimer mt(ms);
usleep(1000 * ms);
int32_t r = mt.remaining();
// 1ms slush, for the cost of calling usleep.
EXPECT_NEAR(r+1, 0, 1);
}
}
TEST(timer_tests, overlapping_long_intervals) {
MillisecondTimer* timers[10];
// Experimentally determined. Corresponds to the extra time taken by the loops,
// the big usleep, and the test infrastructure itself.
const int slush_factor = 14;
// Set up the timers to each time one second, 1ms apart.
for (int t = 0; t < 10; t++)
{
timers[t] = new MillisecondTimer(1000);
usleep(1000);
}
// Check in on them after 500ms.
usleep(500000);
for (int t = 0; t < 10; t++)
{
EXPECT_NEAR(timers[t]->remaining(), 500 - slush_factor + t, 5);
}
// Check in on them again after another 500ms and free them.
usleep(500000);
for (int t = 0; t < 10; t++)
{
EXPECT_NEAR(timers[t]->remaining(), -slush_factor + t, 5);
delete timers[t];
}
}
} // namespace
int main(int argc, char **argv) {
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}
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