Resume a stopped test session

[AndrewFalanga]

I have been looking into this for a few hours now. I haven't found much.

What I need to resume a session which was stopped, probably due to loss of power. Is this possible? I have found very little via many Google searches and time on Stackoverflow. The closes I've found thus far is this http://lists.idyll.org/pipermail/testing-in-python/2018-January/007157.html. At that time, the OP was told that "support for this didn't yet exist." It's 3 years later, has this changed?

If it hasn't changed, what sort of things would be important if writing our own set of plugins to support such a feature?

Thanks,
Andrew

[nicoddemus]

Hi @AndrewFalanga,

Currently there's no native support for that, but the OP in the message comments that he managed to write a simple plugin that does this as he intends.

I suggest to follow the same idea, should be relatively simple, here's a quick outline:

1. Implement pytest_runtest_protocol as a hookwrapper: when the wrapper "ends", it means the test ran to completion, so record the test node id in a specific file on disk.
2. When the test session finishes (implement pytest_sessionfinish), delete that file from disk to indicate a complete run.
3. When running for the second time, implement pytest_collection_modifyitems, which then should see if the file exists: if it does, it should remove the node ids from the collection that are in the file, because the file's existence indicates a previous run terminated abruptly, so those items have already executed and we should resume from that point.

Hope this helps!

[AndrewFalanga]

Thank @nicoddemus for the pointers on implementing the plugins which will be required to do these actions. This will greatly reduce the time for implementation.

[AndrewFalanga]

@nicoddemus I've been working on this for a bit now and I have a question about properly deselecting these things. My current process is to simply <list>.pop() the items which have the nodeid that I write to the file. This does work however it doesn't seem that it's the correct way to remove them. How do I modify what is selected and deselected in a correct way?

[graingert]

have a look at the stepwise plugin

pytest/src/_pytest/stepwise.py

Line 65 in bb9683d

def pytest_collection_modifyitems(

[AndrewFalanga]

@graingert thank you. That is very intriguing.

[graingert]

I think writing the test state (collected/started/passed/failed) to sqlite would probably be the safest

this way sqlite can handle terminating during a run safely without corrupting the file

I'd love something like --stepwise that works with pytest-xdist and pytest-randomly and it sounds like that's what you're writing?