Write integration tests for Observer about pathspider

[irl]

Integration testing will have to happen in a later release, but we're starting to write unit tests.

[irl]

We have now "it can run over the packets and check the correct number of flows exist". We still need plugin specific tests for the chain functions.

[irl]

Need testing for each of the plugins:

• ECN
• DSCP
• TFO
• TLS (waiting for #66)

[irl]

Once DSCP and TFO are covered, this is done for 1.0.0 and can be reassigned to 1.1.0.

@britram Can you provide a test trace for TFO?

[britram]

test trace committed

[irl]

These are basically all here now, closing this issue. We can open new issues for individual plugins if needed in the future.