Allow event-loop signal tests to pass on FreeBSD

On Linux the signal will be immediately visible in the epoll_wait() call.
However, on FreeBSD we may need a small delay between kill() call and the
signal being visible to the kevent() call. This sometimes happens when the
signal processing and kevent processing runs on different CPUs in the
kernel, so becomes more likely when the system is under load (e.g. running
all tests in parallel).

See https://github.com/jiixyj/epoll-shim/pull/32

Signed-off-by: Alex Richardson <Alexander.Richardson@cl.cam.ac.uk>

1 files changed, 27 insertions, 7 deletions

diff --git a/tests/event-loop-test.c b/tests/event-loop-test.c
index cbeaf8e..9d43c91 100644
--- a/tests/event-loop-test.c
+++ b/tests/event-loop-test.c
@@ -168,10 +168,22 @@ TEST(event_loop_signal)
 					  signal_callback, &got_it);
 	assert(source);
 
-	wl_event_loop_dispatch(loop, 0);
+	assert(wl_event_loop_dispatch(loop, 0) == 0);
 	assert(!got_it);
-	kill(getpid(), SIGUSR1);
-	wl_event_loop_dispatch(loop, 0);
+	assert(kill(getpid(), SIGUSR1) == 0);
+	/*
+	 * On Linux the signal will be immediately visible in the epoll_wait()
+	 * call. However, on FreeBSD we may need a small delay between kill()
+	 * call and the signal being visible to the kevent() call. This
+	 * sometimes happens when the signal processing and kevent processing
+	 * runs on different CPUs, so becomes more likely when the system is
+	 * under load (e.g. running all tests in parallel).
+	 * See https://github.com/jiixyj/epoll-shim/pull/32
+	 * Passing 1ms as the timeout appears to avoid this race condition in
+	 * all cases tested so far, but to be safe we use 1000ms which should
+	 * be enough time even on a really slow (or emulated) system.
+	 */
+	assert(wl_event_loop_dispatch(loop, 1000) == 0);
 	assert(got_it == 1);
 
 	wl_event_source_remove(source);
@@ -199,8 +211,12 @@ TEST(event_loop_multiple_same_signals)
 	/* Try it more times */
 	for (i = 0; i < 5; ++i) {
 		calls_no = 0;
-		kill(getpid(), SIGUSR1);
-		assert(wl_event_loop_dispatch(loop, 0) == 0);
+		assert(kill(getpid(), SIGUSR1) == 0);
+		/*
+		 * We need a non-zero timeout here to allow the test to pass
+		 * on non-Linux systems (see comment in event_loop_signal).
+		 */
+		assert(wl_event_loop_dispatch(loop, 1000) == 0);
 		assert(calls_no == 2);
 	}
 
@@ -208,8 +224,12 @@ TEST(event_loop_multiple_same_signals)
 
 	/* Try it again  with one source */
 	calls_no = 0;
-	kill(getpid(), SIGUSR1);
-	assert(wl_event_loop_dispatch(loop, 0) == 0);
+	assert(kill(getpid(), SIGUSR1) == 0);
+	/*
+	 * We need a non-zero timeout here to allow the test to pass
+	 * on non-Linux systems (see comment in event_loop_signal).
+	 */
+	assert(wl_event_loop_dispatch(loop, 1000) == 0);
 	assert(calls_no == 1);
 
 	wl_event_source_remove(s2);