def test_fails_for_bad_ihl(self):
payload = factory.make_bytes(48)
packet = make_ipv4_packet(payload=payload, ihl=0)
ipv4 = IPv4(packet)
self.assertThat(ipv4.is_valid(), Equals(False))
self.assertThat(ipv4.invalid_reason,
DocTestMatches("Invalid IPv4 IHL..."))
def test_fails_for_non_ipv4_packet(self):
payload = factory.make_bytes(48)
packet = make_ipv4_packet(payload=payload, version=5)
ipv4 = IPv4(packet)
self.assertThat(ipv4.is_valid(), Equals(False))
self.assertThat(ipv4.invalid_reason,
DocTestMatches("Invalid version..."))
def test_parses_ipv4_packet(self):
payload = factory.make_bytes(48)
packet = make_ipv4_packet(payload=payload)
ipv4 = IPv4(packet)
self.assertThat(ipv4.is_valid(), Equals(True))
self.assertThat(ipv4.version, Equals(4))
self.assertThat(ipv4.ihl, Equals(20))
self.assertThat(ipv4.payload, Equals(payload))
def test_fails_for_truncated_packet(self):
packet = make_ipv4_packet(truncated=True)
ipv4 = IPv4(packet)
self.assertThat(ipv4.is_valid(), Equals(False))
self.assertThat(ipv4.invalid_reason, DocTestMatches("Truncated..."))
