test: fix test_liquidity_hints test case

[3nprob]

Since all fees are equal it's arbitrary which one gets chosen - but it does seem like this case consistently gets A>B>E selected.

Maybe making the fees in the channels of the graph not equal could be worth considering in order to ensure that there is a single correct answer and that the shortest path indeed does get chosen given equal lengths - but for now this should at least make it pass as-is.

Also fixes import paths so one can run individual tests by e.g. python3 lndmanage:test -m unittest discover -p 'test_pathfinding.py'

[3nprob]

Rebased on master

[bitromortac]

There's something strange going on here. Tests depend on order of execution.

[bitromortac]

The path weights are not equal by default even though the fees are all the same. The reason behind this is the probability factor which depends on the channel capacity, which are different. The problem here is that if the test is run in isolation or together with others, liquidity hints are loaded or not present. The correct outcome should be A -> B -> E. Need to think more about Network side effects.

Should get really rid of these side effects. Could you change it to:

    with mock.patch.object(Network, 'load_graph', return_value=None):
        network = Network(MockNode())
        network.graph = nx.MultiGraph()
        network.edges = {}
        # TODO: fix side effects of liquidity hints loading
        network.liquidity_hints = LiquidityHintMgr(MockNode.pub_key)

[3nprob]

Ah, missed that gotcha there - and agreed on the todo!

Updated it now as requested. Also verified that each test .py completes successfully both independently and as part of a full suite run.

[bitromortac]

Thank you for pushing these investigations!