[libgpiod][PATCH 1/2] tests: event: reading test coverage extended to cover reading a subset of available events

[Kent Gibson <warthog618@xxxxxxxxx>]

Add tests for gpiod_line_event_read(), including reading multiple
entries from the kernel event kfifo, and extend the existing
read_multiple_event tests to read a subset of the available events as
well as all the available events.

Signed-off-by: Kent Gibson <warthog618@xxxxxxxxx>
---

I have removed the usleep()s between setting the pulls on the mockup as
I don't believe they are necessary.
Setting the pulls results in serial writes to the debugfs, which the
kernel should be able to deal with.
Any queuing in the kernel that results should come out in the wash.

 tests/tests-event.c | 144 ++++++++++++++++++++++++++++++++++++++------
 1 file changed, 124 insertions(+), 20 deletions(-)

diff --git a/tests/tests-event.c b/tests/tests-event.c
index e323060..c1f73d4 100644
--- a/tests/tests-event.c
+++ b/tests/tests-event.c
@@ -663,13 +663,74 @@ GPIOD_TEST_CASE(invalid_fd, 0, { 8 })
 	g_assert_cmpint(errno, ==, EINVAL);
 }
 
+GPIOD_TEST_CASE(read_event, 0, { 8 })
+{
+	g_autoptr(gpiod_chip_struct) chip = NULL;
+	struct timespec ts = { 1, 0 };
+	struct gpiod_line_event ev;
+	struct gpiod_line *line;
+	gint ret;
+	unsigned int i;
+
+	chip = gpiod_chip_open(gpiod_test_chip_path(0));
+	g_assert_nonnull(chip);
+	gpiod_test_return_if_failed();
+
+	line = gpiod_chip_get_line(chip, 7);
+	g_assert_nonnull(line);
+	gpiod_test_return_if_failed();
+
+	ret = gpiod_line_request_both_edges_events_flags(line,
+		GPIOD_TEST_CONSUMER, GPIOD_LINE_REQUEST_FLAG_BIAS_PULL_UP);
+	g_assert_cmpint(ret, ==, 0);
+
+	/* generate multiple events */
+	for (i = 0; i < 3; i++)
+		gpiod_test_chip_set_pull(0, 7, i & 1);
+
+	/* read them individually... */
+	ret = gpiod_line_event_wait(line, &ts);
+	g_assert_cmpint(ret, ==, 1);
+	if (!ret)
+		return;
+
+	ret = gpiod_line_event_read(line, &ev);
+	g_assert_cmpint(ret, ==, 0);
+
+	g_assert_cmpint(ev.event_type, ==, GPIOD_LINE_EVENT_FALLING_EDGE);
+
+	ret = gpiod_line_event_wait(line, &ts);
+	g_assert_cmpint(ret, ==, 1);
+	if (!ret)
+		return;
+
+	ret = gpiod_line_event_read(line, &ev);
+	g_assert_cmpint(ret, ==, 0);
+
+	g_assert_cmpint(ev.event_type, ==, GPIOD_LINE_EVENT_RISING_EDGE);
+
+	ret = gpiod_line_event_wait(line, &ts);
+	g_assert_cmpint(ret, ==, 1);
+	if (!ret)
+		return;
+
+	ret = gpiod_line_event_read(line, &ev);
+	g_assert_cmpint(ret, ==, 0);
+
+	g_assert_cmpint(ev.event_type, ==, GPIOD_LINE_EVENT_FALLING_EDGE);
+
+	ret = gpiod_line_event_wait(line, &ts);
+	g_assert_cmpint(ret, ==, 0);
+}
+
 GPIOD_TEST_CASE(read_multiple_events, 0, { 8 })
 {
 	g_autoptr(gpiod_chip_struct) chip = NULL;
-	struct gpiod_line_event events[3];
+	struct gpiod_line_event events[5];
 	struct timespec ts = { 1, 0 };
 	struct gpiod_line *line;
 	gint ret;
+	unsigned int i;
 
 	chip = gpiod_chip_open(gpiod_test_chip_path(0));
 	g_assert_nonnull(chip);
@@ -682,22 +743,16 @@ GPIOD_TEST_CASE(read_multiple_events, 0, { 8 })
 	ret = gpiod_line_request_both_edges_events(line, GPIOD_TEST_CONSUMER);
 	g_assert_cmpint(ret, ==, 0);
 
-	gpiod_test_chip_set_pull(0, 4, 1);
-	/*
-	 * We sleep for a short period of time here and in other test cases
-	 * for multiple events to let the kernel service each simulated
-	 * interrupt. Otherwise we'd risk triggering an interrupt while the
-	 * previous one is still being handled.
-	 */
-	usleep(10000);
-	gpiod_test_chip_set_pull(0, 4, 0);
-	usleep(10000);
-	gpiod_test_chip_set_pull(0, 4, 1);
-	usleep(10000);
+	/* generate multiple events */
+	for (i = 0; i < 7; i++)
+		gpiod_test_chip_set_pull(0, 4, !(i & 1));
 
 	ret = gpiod_line_event_wait(line, &ts);
 	g_assert_cmpint(ret, ==, 1);
+	if (!ret)
+		return;
 
+	/* read a chunk */
 	ret = gpiod_line_event_read_multiple(line, events, 3);
 	g_assert_cmpint(ret, ==, 3);
 
@@ -707,15 +762,40 @@ GPIOD_TEST_CASE(read_multiple_events, 0, { 8 })
 			GPIOD_LINE_EVENT_FALLING_EDGE);
 	g_assert_cmpint(events[2].event_type, ==,
 			GPIOD_LINE_EVENT_RISING_EDGE);
+
+	ret = gpiod_line_event_wait(line, &ts);
+	g_assert_cmpint(ret, ==, 1);
+	if (!ret)
+		return;
+
+	/*
+	 * read the remainder
+	 * - note the attempt to read more than are available
+	 */
+	ret = gpiod_line_event_read_multiple(line, events, 5);
+	g_assert_cmpint(ret, ==, 4);
+
+	g_assert_cmpint(events[0].event_type, ==,
+			GPIOD_LINE_EVENT_FALLING_EDGE);
+	g_assert_cmpint(events[1].event_type, ==,
+			GPIOD_LINE_EVENT_RISING_EDGE);
+	g_assert_cmpint(events[2].event_type, ==,
+			GPIOD_LINE_EVENT_FALLING_EDGE);
+	g_assert_cmpint(events[3].event_type, ==,
+			GPIOD_LINE_EVENT_RISING_EDGE);
+
+	ret = gpiod_line_event_wait(line, &ts);
+	g_assert_cmpint(ret, ==, 0);
 }
 
 GPIOD_TEST_CASE(read_multiple_events_fd, 0, { 8 })
 {
 	g_autoptr(gpiod_chip_struct) chip = NULL;
-	struct gpiod_line_event events[3];
+	struct gpiod_line_event events[5];
 	struct timespec ts = { 1, 0 };
 	struct gpiod_line *line;
 	gint ret, fd;
+	unsigned int i;
 
 	chip = gpiod_chip_open(gpiod_test_chip_path(0));
 	g_assert_nonnull(chip);
@@ -728,19 +808,19 @@ GPIOD_TEST_CASE(read_multiple_events_fd, 0, { 8 })
 	ret = gpiod_line_request_both_edges_events(line, GPIOD_TEST_CONSUMER);
 	g_assert_cmpint(ret, ==, 0);
 
-	gpiod_test_chip_set_pull(0, 4, 1);
-	usleep(10000);
-	gpiod_test_chip_set_pull(0, 4, 0);
-	usleep(10000);
-	gpiod_test_chip_set_pull(0, 4, 1);
-	usleep(10000);
+	/* generate multiple events */
+	for (i = 0; i < 7; i++)
+		gpiod_test_chip_set_pull(0, 4, !(i & 1));
 
 	ret = gpiod_line_event_wait(line, &ts);
 	g_assert_cmpint(ret, ==, 1);
+	if (!ret)
+		return;
 
 	fd = gpiod_line_event_get_fd(line);
 	g_assert_cmpint(fd, >=, 0);
 
+	/* read a chunk */
 	ret = gpiod_line_event_read_fd_multiple(fd, events, 3);
 	g_assert_cmpint(ret, ==, 3);
 
@@ -750,4 +830,28 @@ GPIOD_TEST_CASE(read_multiple_events_fd, 0, { 8 })
 			GPIOD_LINE_EVENT_FALLING_EDGE);
 	g_assert_cmpint(events[2].event_type, ==,
 			GPIOD_LINE_EVENT_RISING_EDGE);
+
+	ret = gpiod_line_event_wait(line, &ts);
+	g_assert_cmpint(ret, ==, 1);
+	if (!ret)
+		return;
+
+	/*
+	 * read the remainder
+	 * - note the attempt to read more than are available
+	 */
+	ret = gpiod_line_event_read_fd_multiple(fd, events, 5);
+	g_assert_cmpint(ret, ==, 4);
+
+	g_assert_cmpint(events[0].event_type, ==,
+			GPIOD_LINE_EVENT_FALLING_EDGE);
+	g_assert_cmpint(events[1].event_type, ==,
+			GPIOD_LINE_EVENT_RISING_EDGE);
+	g_assert_cmpint(events[2].event_type, ==,
+			GPIOD_LINE_EVENT_FALLING_EDGE);
+	g_assert_cmpint(events[3].event_type, ==,
+			GPIOD_LINE_EVENT_RISING_EDGE);
+
+	ret = gpiod_line_event_wait(line, &ts);
+	g_assert_cmpint(ret, ==, 0);
 }
-- 
2.28.0