Easier replay of failing scheduler

[dubzzz]

🚀 Feature Request

Easier replay of failing scheduler

Motivation

While fast-check offers a simple way to replay failures based on seed and path, schedulers cannot be replayed using the the examples options offered on fc.assert.

While working on the PR facebook/react#18721 on React, I have been challenged on this topic: it should be easier to set custom examples related to schedulers.

Example

Among the possible options here are some that came in my mind to offer this kind of capabilities on schedulers:

fc.assert(
  fc.property(fc.scheduler(), () => {/*code*/}),
  {
    examples: [
      // scheduler resolving tasks in the order 1, 5, 4, 3, 2
      fc.schedulerFor([1, 5, 4, 3, 2]/*, opt constraints*/),
      // same scheduler but this one is one copied and pasted from previous tests failures
      fc.schedulerFor(/*opt constraints*/)`
        -> [task#${1}] promise pending
        -> [task#${5}] promise pending
        -> [task#${4}] promise pending
        -> [task#${3}] promise pending
        -> [task#${2}] promise pending
      ` 
    ]
  }
);

One of the issue we have today is that fc.scheduler can be receive a custom act function and we will also need to pass it to the schedulerFor and this why we use schedulerFor(). Alternatively we may configure this custom act later in the code 🤔