AmosHason/busypie

Expressive busy wait for Python

Easy and expressive busy-waiting for Python

Intro

Although you wouldn't want to do much busy waiting in your production code, testing is a different matter. When testing asynchronous systems, it's very helpful to wait for some scenario to finish its course. BusyPie helps you perform busy waiting easily and expressively.

Installation

To install it using pip

python -m pip install busypie

To include it in requirements.txt file add

busypie==0.4.3

Example

Most typical usage will be in test, when we have a scenario that require us to wait for something to happen.

def test_event_should_be_dispatched():
    dispatcher.dispatch(event)
    wait().at_most(2, SECOND).until(event_dispatched)

Usage

Wait for a condition. Default wait time is 10 seconds. until() will return the final result of the condition function

wait().until(condition_function)
wait().during(condition_function)

Python async support. until_async() will return the final result of the condition function.

await wait().until_async(condition_function)
await wait().during_async(condition_function)

Specify maximum time to meet the condition

wait().at_most(FIVE_SECONDS).until(condition_function)
wait_at_most(FIVE_SECONDS).until(condition_function)
wait().at_most(10, SECOND).until(condition_function)
wait_at_most(10, SECOND).until(condition_function)    

Ignoring exceptions thrown from a condition function

given().ignore_exceptions().wait().until(condition_function)
wait().ignore_exceptions(ZeroDevisionError).until(condition_function)

Add custom description to show up in timeout error message

wait().with_description('check app is running').until(lambda: app_state() == 'UP')

Changing poll interval

wait().poll_interval(FIVE_HUNDRED_MILLISECONDS).until(condition_function)
wait().poll_interval(2, SECOND).until(condition_function)

Changing polling delay

wait().poll_delay(SECOND).during(app_is_pending)

Changing the default values of busypie

set_default_timeout(60, SECOND) # Default is 10 seconds

Resetting default values

reset_defaults()

Credits

This project drew a lot of inspiration from Awaitility.