Release 0.18.0

[northernSage]

Our 0.18.0 release 🎉

Change summary:

Public

• ProcessInfo.terminate will now terminate outer leaves in process tree first and work its way towards root process. For example, if a process has child and grandchild, xprocess will terminate first child and grandchild and only then will the root process receive a termination signal.

• ProcessStarter now has terminate_on_interrupt. This flag will
  make xprocess attempt to terminate and clean up all started process resources
  upon interruptions during pytest runs (CTRL+C, SIGINT and internal errors)
  when set to True. It will default to False, so if the described behaviour
  is desired the flag must be explicitly set True.

• Add a new popen_kwargs variable to ProcessStarter, this variable can
  be used for passing keyword values to the subprocess.Popen constructor,
  giving the user more control over how the process is initialized.

Internal

• Process Clean-up logic moved to XProcess class. Also, only processes with a termination_signal issued will be waited during tear-down, as opposed to assuming that all processes would always be terminated by the end of the test run and waiting on all Popen instances exit code.

[northernSage]

I have noticed just know due to a totally unrelated PR (#74) that 0.18.0 may have introduced some flaky termination behaviour.

From CI raw logs:

FAILED test_functional_workflow.py::test_functional_work_flow
FAILED test_process_termination.py::test_clean_shutdown[6777-s1] - AssertionE..
...
6-29T22:46:03.6561320Z > result.stdout.fnmatch_lines("TERMINATED")
2021-06-29T22:46:03.6562270Z E Failed: nomatch: 'TERMINATED'
2021-06-29T22:46:03.6563150Z E and: '1231 server_workflow_test FAILED TO TERMINATE'
2021-06-29T22:46:03.6565050Z E and: "pytest-xprocess reminder::Be sure to terminate the started process by running 'pytest --xkill' if you have not explicitly done so in your fixture with 'xprocess.getinfo(<process_name>).terminate()'."
2021-06-29T22:46:03.6566460Z E remains unmatched: 'TERMINATED'
...

So I'll have to look into that before the release can happen 😞

I have create an issue to address this: #75

[northernSage]

The flaky behaviour seems to be fixed so we should be good to go. WDYT @nicoddemus ?

[nicoddemus]

Sounds good, thanks for tackling this!