fix integration tests for bandwidth measurements

[david415]

Currently in the develop branch we have a couple of integration test classes set to be skipped because these tests contain race conditions. The race condition has to do with not sending enough cells over a circuit to make a proper bandwidth estimate because the circuit is closed too quickly after sending the entire test payload.

btw i am calling them integration tests since they require chutney instead of utilizing mock patterns.

[DonnchaC]

The problem is not that it doesn't send enough cells, its because the test payload transmission does not take long enough. The Tor control port only emits bandwidth events approx. once per second. We need to make sure the payload transmission takes at least a couple of seconds in order to ensure we have enough measurements to perform the bandwidth calculations.

[david415]

some failed attempts in my dev branches to slow the test server protocol:
https://github.com/david415/bwscanner/tree/fix_tests.3
https://github.com/david415/bwscanner/tree/fix_tests.2
...

[david415]

It could be that the twisted web agent class disconnects from the server if a malformed response is received... that might be why my dev branches don't work; @DonnchaC pointed out that the bug on this line which would cause malformed responses from the server:
https://github.com/david415/bwscanner/blob/fix_tests.3/test/test_listener.py#L60

I haven't yet tried fixing it and seeing if the tests pass.

[DonnchaC]

I don't thing that bug is causing an issue in this case. Size is always set to 1, so the call offset+1 and offset+size are equivalent. It should be fixed in case we are using different sized chunks in future.

[DonnchaC]

StreamBandwidthListener() is currently not being used for generating measurements. It is just included in test_listener.py. As the tests for this code don't pass, I think that this code and tests should be removed for now. PR in #21