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Interface: Scheduler<TMetaData>

Defined in: packages/fast-check/src/arbitrary/_internals/interfaces/Scheduler.ts:23

Instance able to reschedule the ordering of promises for a given app

Remarks

Since 1.20.0

Type Parameters

Type ParameterDefault type
TMetaDataunknown

Properties

report

report: () => SchedulerReportItem<TMetaData>[]

Defined in: packages/fast-check/src/arbitrary/_internals/interfaces/Scheduler.ts:131

Produce an array containing all the scheduled tasks so far with their execution status. If the task has been executed, it includes a string representation of the associated output or error produced by the task if any.

Tasks will be returned in the order they get executed by the scheduler.

Returns

SchedulerReportItem<TMetaData>[]

Remarks

Since 1.25.0


schedule

schedule: <T>(task, label?, metadata?, customAct?) => Promise<T>

Defined in: packages/fast-check/src/arbitrary/_internals/interfaces/Scheduler.ts:28

Wrap a new task using the Scheduler

Type Parameters

Type Parameter
T

Parameters

ParameterType
taskPromise<T>
label?string
metadata?TMetaData
customAct?SchedulerAct

Returns

Promise<T>

Remarks

Since 1.20.0


scheduleFunction

scheduleFunction: <TArgs, T>(asyncFunction, customAct?) => (...args) => Promise<T>

Defined in: packages/fast-check/src/arbitrary/_internals/interfaces/Scheduler.ts:34

Automatically wrap function output using the Scheduler

Type Parameters

Type Parameter
TArgs extends any[]
T

Parameters

ParameterType
asyncFunction(...args) => Promise<T>
customAct?SchedulerAct

Returns

(...args) => Promise<T>

Remarks

Since 1.20.0


waitAll

waitAll: (customAct?) => Promise<void>

Defined in: packages/fast-check/src/arbitrary/_internals/interfaces/Scheduler.ts:82

Wait all scheduled tasks, including the ones that might be created by one of the resolved task

Parameters

ParameterType
customAct?SchedulerAct

Returns

Promise<void>

Remarks

Since 1.20.0

Deprecated

Use waitIdle() instead, it comes with a more predictable behavior awaiting all scheduled and reachable tasks to be completed


waitFor

waitFor: <T>(unscheduledTask, customAct?) => Promise<T>

Defined in: packages/fast-check/src/arbitrary/_internals/interfaces/Scheduler.ts:121

Wait as many scheduled tasks as need to resolve the received Promise

Some tests frameworks like supertest are not triggering calls to subsequent queries in a synchronous way, some are waiting an explicit call to then to trigger them (either synchronously or asynchronously)... As a consequence, none of waitOne or waitAll cannot wait for them out-of-the-box.

This helper is responsible to wait as many scheduled tasks as needed (but the bare minimal) to get unscheduledTask resolved. Once resolved it returns its output either success or failure.

Be aware that while this helper will wait eveything to be ready for unscheduledTask to resolve, having uncontrolled tasks triggering stuff required for unscheduledTask might be a source a uncontrollable and not reproducible randomness as those triggers cannot be handled and scheduled by fast-check.

Type Parameters

Type Parameter
T

Parameters

ParameterType
unscheduledTaskPromise<T>
customAct?SchedulerAct

Returns

Promise<T>

Remarks

Since 2.24.0


waitIdle

waitIdle: (customAct?) => Promise<void>

Defined in: packages/fast-check/src/arbitrary/_internals/interfaces/Scheduler.ts:103

Wait until the scheduler becomes idle: all scheduled and reachable tasks have completed.

It will include tasks scheduled by other tasks, recursively.

Note: Tasks triggered by uncontrolled sources (like fetch or external events) cannot be detected or awaited and may lead to incomplete waits.

If you want to wait for a precise event to happen you should rather opt for waitFor or waitNext given they offer you a more granular control on what you are exactly waiting for.

Parameters

ParameterType
customAct?SchedulerAct

Returns

Promise<void>

Remarks

Since 4.2.0


waitNext

waitNext: (count, customAct?) => Promise<void>

Defined in: packages/fast-check/src/arbitrary/_internals/interfaces/Scheduler.ts:88

Wait and schedule exactly count scheduled tasks.

Parameters

ParameterType
countnumber
customAct?SchedulerAct

Returns

Promise<void>

Remarks

Since 4.2.0


waitOne

waitOne: (customAct?) => Promise<void>

Defined in: packages/fast-check/src/arbitrary/_internals/interfaces/Scheduler.ts:74

Wait one scheduled task to be executed

Parameters

ParameterType
customAct?SchedulerAct

Returns

Promise<void>

Throws

Whenever there is no task scheduled

Remarks

Since 1.20.0

Deprecated

Use waitNext(1) instead, it comes with a more predictable behavior

Methods

count()

count(): number

Defined in: packages/fast-check/src/arbitrary/_internals/interfaces/Scheduler.ts:66

Count of pending scheduled tasks

Returns

number

Remarks

Since 1.20.0


scheduleSequence()

scheduleSequence(sequenceBuilders, customAct?): object

Defined in: packages/fast-check/src/arbitrary/_internals/interfaces/Scheduler.ts:53

Schedule a sequence of Promise to be executed sequencially. Items within the sequence might be interleaved by other scheduled operations.

Please note that whenever an item from the sequence has started, the scheduler will wait until its end before moving to another scheduled task.

A handle is returned by the function in order to monitor the state of the sequence. Sequence will be marked:

  • done if all the promises have been executed properly
  • faulty if one of the promises within the sequence throws

Parameters

ParameterType
sequenceBuildersSchedulerSequenceItem<TMetaData>[]
customAct?SchedulerAct

Returns

object

done

done: boolean

faulty

faulty: boolean

task

task: Promise<{ done: boolean; faulty: boolean; }>

Remarks

Since 1.20.0