Tests for twisted.pair.tuntap.
| Class | ReactorFDSet | An implementation of IReactorFDSetwhich only keeps track of which descriptors have been registered for 
reading and writing. | 
| Class | FSSetClock | An FSSetClockis aIReactorFDSetand anIReactorClock. | 
| Class | TunHelper | A helper for tests of tun-related functionality (ip-level tunnels). | 
| Class | TapHelper | A helper for tests of tap-related functionality (ethernet-level tunnels). | 
| Class | TunnelTests | Tunnelis 
mostly tested by other test cases but some tests don't fit there.  Those 
tests are here. | 
| Class | TunnelDeviceTestsMixin | A mixin defining tests that apply to _IInputOutputSystemimplementations. | 
| Class | FakeDeviceTestsMixin | Define a mixin for use with test cases that require an _IInputOutputSystemprovider.  This mixin hands outMemoryIOSysteminstances as the provider of that interface. | 
| Class | FakeTapDeviceTests | Run various tap-type tunnel unit tests against an in-memory I/O system. | 
| Class | FakeTapDeviceWithPITests | Run various tap-type tunnel unit tests against an in-memory I/O system with the PI header enabled. | 
| Class | FakeTunDeviceTests | Run various tun-type tunnel unit tests against an in-memory I/O system. | 
| Class | TestRealSystem | Add extra skipping logic so tests that try to create real tunnel devices on platforms where those are not supported automatically get skipped. | 
| Class | RealDeviceTestsMixin | Define a mixin for use with test cases that require an _IInputOutputSystemprovider.  This mixin hands outTestRealSysteminstances as the provider of that interface. | 
| Class | RealDeviceWithProtocolInformationTests | Run various tap-type tunnel unit tests, with "protocol information" (PI) turned on, against a real I/O system. | 
| Class | RealDeviceWithoutProtocolInformationTests | Run various tap-type tunnel unit tests, with "protocol information" (PI) turned off, against a real I/O system. | 
| Class | TuntapPortTests | Tests for TuntapPortbehavior that is independent of the tunnel type. | 
| Class | TunnelTestsMixin | A mixin defining tests for TuntapPort. | 
| Class | TunnelAddressTests | Tests for TunnelAddress. | 
| Class | TunnelAddressEqualityTests | Tests for the implementation of equality ( ==and!=) forTunnelAddress. | 
| Class | IPRecordingProtocol | A protocol which merely records the datagrams delivered to it. | 
| Class | TunTests | Tests for TuntapPortwhen
used to open a Linux tun tunnel. | 
| Class | EthernetRecordingProtocol | A protocol which merely records the datagrams delivered to it. | 
| Class | TapTests | Tests for TuntapPortwhen
used to open a Linux tap tunnel. | 
| Class | IOSystemTestsMixin | Tests that apply to any _IInputOutputSystemimplementation. | 
| Class | MemoryIOSystemTests | General _IInputOutputSystemtests applied toMemoryIOSystem. | 
| Class | RealIOSystemTests | General _IInputOutputSystemtests applied to_RealSystem. |