def test_parse_silabs_gbl():
list(validators.parse_silabs_gbl(VALID_GBL_IMAGE))
image = create_gbl_image([(b"AAAA", b"test"), (b"BBBB", b"foo" * 20)])
header, tag1, tag2, checksum = validators.parse_silabs_gbl(image)
assert header[0] == b"\xEB\x17\xA6\x03" and len(header[1]) == 8
assert tag1 == (b"AAAA", b"test")
assert tag2 == (b"BBBB", b"foo" * 20)
assert checksum[0] == b"\xFC\x04\x04\xFC" and len(checksum[1]) == 4
# Arbitrary padding is allowed
parsed_image = [header, tag1, tag2, checksum]
assert list(validators.parse_silabs_gbl(image + b"\x00")) == parsed_image
assert list(validators.parse_silabs_gbl(image +
b"\xAB\xCD\xEF")) == parsed_image
# Normal truncated images are detected
with pytest.raises(ValidationError):
list(validators.parse_silabs_gbl(image[-10:]))
# Structurally sound but truncated images are detected
with pytest.raises(ValidationError):
offset = image.index(b"test")
bad_image = image[:offset - 8]
list(validators.parse_silabs_gbl(bad_image))
# Corrupted images are detected
with pytest.raises(ValidationError):
corrupted_image = image.replace(b"foo", b"goo", 1)
assert image != corrupted_image
list(validators.parse_silabs_gbl(corrupted_image))
def create_gbl_image(tags):
# All images start with an 8-byte header
tags = [(b"\xEB\x17\xA6\x03", b"\x00\x00\x00\x03\x01\x01\x00\x00")] + tags
assert all([len(tag) == 4 for tag, value in tags])
image = b"".join(tag + len(value).to_bytes(4, "little") + value
for tag, value in tags)
# And end with a checksum
image += (b"\xFC\x04\x04\xFC" + b"\x04\x00\x00\x00" +
zlib.crc32(image + b"\xFC\x04\x04\xFC" +
b"\x04\x00\x00\x00").to_bytes(4, "little"))
assert list(validators.parse_silabs_gbl(image))
return image