Phase Groups Example

The upstream phase_groups.py example — six runs showing exactly when OpenHTF executes teardown phases after setup errors, main errors, nested groups and errors inside nested groups.

Six short tests that answer one question each: does teardown run? Based on examples/phase_groups.py.

phase_groups.py

import openhtf as htf


def setup_phase(test):
    test.logger.info('Setup in a group.')

def main_phase(test):
    test.logger.info('This is a main phase.')

def teardown_phase(test):
    test.logger.info('Teardown phase.')

def inner_main_phase(test):
    test.logger.info('Inner main phase.')

def inner_teardown_phase(test):
    test.logger.info('Inner teardown phase.')

def error_setup_phase(test):
    test.logger.info('Error in setup phase.')
    return htf.PhaseResult.STOP

def error_main_phase(test):
    test.logger.info('Error in main phase.')
    return htf.PhaseResult.STOP


def run_basic_group():
    """No terminal phase: setup, main, teardown all run."""
    htf.Test(htf.PhaseGroup(
        setup=[setup_phase], main=[main_phase], teardown=[teardown_phase],
    )).execute()


def run_setup_error_group():
    """Setup fails: main AND teardown are skipped — the group was never entered."""
    htf.Test(htf.PhaseGroup(
        setup=[error_setup_phase], main=[main_phase], teardown=[teardown_phase],
    )).execute()


def run_main_error_group():
    """Main fails: remaining main phases skipped, teardown still runs."""
    htf.Test(htf.PhaseGroup(
        setup=[setup_phase], main=[error_main_phase, main_phase], teardown=[teardown_phase],
    )).execute()


def run_nested_groups():
    """Nested group, no error: main, inner main, inner teardown, teardown."""
    htf.Test(htf.PhaseGroup(
        main=[
            main_phase,
            htf.PhaseGroup.with_teardown(inner_teardown_phase)(inner_main_phase),
        ],
        teardown=[teardown_phase],
    )).execute()


def run_nested_error_groups():
    """Error inside the nested group: inner teardown, then outer teardown."""
    htf.Test(htf.PhaseGroup(
        main=[
            htf.PhaseGroup.with_teardown(inner_teardown_phase)(error_main_phase, main_phase),
            main_phase,
        ],
        teardown=[teardown_phase],
    )).execute()


def run_nested_error_skip_unentered_groups():
    """Error before the nested group: it is never entered, only outer teardown runs."""
    htf.Test(htf.PhaseGroup(
        main=[
            error_main_phase,
            htf.PhaseGroup.with_teardown(inner_teardown_phase)(main_phase),
            main_phase,
        ],
        teardown=[teardown_phase],
    )).execute()


def main():
    run_basic_group()
    run_setup_error_group()
    run_main_error_group()
    run_nested_groups()
    run_nested_error_groups()
    run_nested_error_skip_unentered_groups()


if __name__ == '__main__':
    main()

Run with -v to see which phases execute:

Terminal

$ python phase_groups.py -v
I ... <phase: setup_phase> - Setup in a group.
I ... <phase: main_phase> - This is a main phase.
I ... <phase: teardown_phase> - Teardown phase.
======================= test: openhtf_test  outcome: PASS ======================
I ... <phase: error_setup_phase> - Error in setup phase.
======================= test: openhtf_test  outcome: FAIL ======================
I ... <phase: setup_phase> - Setup in a group.
I ... <phase: error_main_phase> - Error in main phase.
I ... <phase: teardown_phase> - Teardown phase.
======================= test: openhtf_test  outcome: FAIL ======================
...

The six outcomes

Scenario	Phases that run	Teardown?
No error	setup → main → teardown	Yes
Setup returns `STOP`	setup only	No — group never entered
Main returns `STOP`	setup → failing main → teardown	Yes; other main phases skipped
Nested, no error	main → inner main → inner teardown → teardown	Both
Error in nested main	inner error → inner teardown → outer teardown	Both; remaining outer main skipped
Error before nested group	outer error → outer teardown	Outer only — inner never entered

Rule of thumb: a group's teardown runs if and only if its setup completed. "Entered" is the word upstream uses.

What it shows

PhaseGroup(setup=, main=, teardown=)

The explicit form. Each argument is a list of phases or nested nodes. Phase Groups →

PhaseGroup.with_teardown(td)(*main)

Shorthand factory: a group with only main and teardown. with_setup and with_context(setup, teardown) exist too.

test.execute() with no DUT ID

Allowed; the record gets UNKNOWN_DUT. Fine for a demo, not for production — see Device Under Test.

Phase Groups

Execution rules and shorthand decorators.

Checkpoints

Stop before an expensive phase when earlier ones failed.

Phase Groups Example

The six outcomes

What it shows

Next

Phase Groups

Checkpoints

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