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pythonpython-hypothesis

Disable shrinking in Hypothesis

I have a test for which I would like to disable the shrinking phase.

I can do this

from hypothesis import given, settings, strategies as st
from hypothesis._settings import Phase

@settings(report_multiple_bugs=False, phases=list(Phase)[:-1])
@given(my_composite_generator())
def test_legacy_rack_conversion(input):
    assert_stuff_about(input)

but I don't like importing private things starting with an underscore from third-party libraries.

Is there a more recommended way to disable shrinking for a test?

Solution

  • See https://hypothesis.readthedocs.io/en/latest/settings.html#controlling-what-runs

    Note that you should from hypothesis import Phase, so there's no private API involved, but also that list(Phase)[:-1] is incorrect - it skips the off-by-default explain phase, not shrinking. Better to explicitly list the phases you want.