tests/extmod: Add coverage tests for select module.

Signed-off-by: Damien George <damien@micropython.org>

1 files changed, 44 insertions, 0 deletions

diff --git a/tests/extmod/select_poll_fd.py b/tests/extmod/select_poll_fd.py
new file mode 100644
index 0000000000..fab9c0e0e9
--- /dev/null
+++ b/tests/extmod/select_poll_fd.py
@@ -0,0 +1,44 @@
+# Test select.poll in combination with file descriptors.
+
+try:
+    import select, errno
+
+    select.poll  # Raises AttributeError for CPython implementations without poll()
+except (ImportError, AttributeError):
+    print("SKIP")
+    raise SystemExit
+
+# Check that poll supports registering file descriptors (integers).
+try:
+    select.poll().register(0)
+except OSError:
+    print("SKIP")
+    raise SystemExit
+
+# Register invalid file descriptor.
+try:
+    select.poll().register(-1)
+except ValueError:
+    print("ValueError")
+
+# Test polling stdout, it should be writable.
+poller = select.poll()
+poller.register(1)
+poller.modify(1, select.POLLOUT)
+print(poller.poll())
+
+# Unregister then re-register.
+poller.unregister(1)
+poller.register(1, select.POLLIN)
+
+# Poll for input, should return an empty list.
+print(poller.poll(0))
+
+# Test registering a very large number of file descriptors.
+poller = select.poll()
+for fd in range(6000):
+    poller.register(fd)
+try:
+    poller.poll()
+except OSError as er:
+    print(er.errno == errno.EINVAL)