def test_teensy_device_get_packet_size_must_never_fail(self):
"""
The Teensy's packet size is preset and must be available and non-zero
even if the device is not connected.
"""
vendor_id = 0
product_id = 0
usage_page = 0
usage = 0
device = TeensyDevice(vendor_id, product_id, usage_page, usage)
self.assertGreater(device.get_packet_size(), 0)
def test_teensy_device_get_vendor_and_product_ids(self):
"""
Test that the VID and PID supplied with the constructor is returned.
"""
vendor_id = 0xA1B2
product_id = 0xC3D4
usage_page = 0xE5F6
usage = 0x1AB2
device = TeensyDevice(vendor_id, product_id, usage_page, usage)
self.assertEqual(device.get_vendor_id(), vendor_id)
self.assertEqual(device.get_product_id(), product_id)
def test_teensy_device_no_such_device(self):
"""
Operations must fail if there's no such device.
"""
# So it seems TeensyRawhid will actually sometimes not raise an IOError
# for an invalid VID and PID (i.e. it will return None as if it has
# successfully opened the device). This is awkward and probably a
# bug -- either in TeensyRawhid or in the kernel. Replicate this by
# executing open(...) consecutively on an interactive Python terminal:
# The first invocation will fail and the subsequent ones succeed. If
# you then wait a while (a few minutes, but I don know exactly how
# long) and try again it will again fail, before succeeding again. What
# does seem to make a difference is to use values greater than zero. It
# will then behave consistently.
vendor_id = 0x1
product_id = 0x1
usage_page = 0x1
usage = 0x1
device = TeensyDevice(vendor_id, product_id, usage_page, usage)
self.assertRaises(IOError, device.open)
self.assertFalse(device.is_open())
self.assertRaises(IOError, device.send, "foo")
self.assertRaises(IOError, device.receive)
