Context

Awaiting provides wait_seconds, wait_frames and wait_for_signal, which are great.

A pattern that often comes up in my tests is to wait for a particular condition to be true.
For example

• repeatedly hit an enemy until it is dead
• hit an enemy then wait until its HP regenerates to 100%
• accelerate something until it has velocity X

In all cases, if a certain timeout is reached, I want the test to fail.

Ideas

Generic wait_until(predicate_func, timeout)

• predicate_func: Callable returning a boolean. Returns true when the success condition is reached
• max_wait: same as wait_for_signal. Timeout after which we stop blocking the test

Fail on max_time reached

I think wait_for_signal and wait_until should fail the test when the max_time is reached, just like a failed assertion.

is_object_freed predicate

GUT could provide a predicate function returning true when an object has been freed.

Other predicates

Many conditions used in assertions would be great as conditions to wait_until if they were converted into predicate functions (excuse the bad names hehe)

await wait_until(has(vegetables_array, 'potato'))
await wait_until(is_signal_connected(signaler, connector, 'the_signal'))
await wait_until(has_call_count(doubled, 'set_value', 1, [4]))

Usage

func test_when_sword_collides_with_wall_then_it_is_stopped() -> void:
  wall = add_child_autofree(WallScene.instantiate())
  wall.set_position(Vector2.RIGHT * 100)
  sword = add_child_autofree(SwordScene.instantiate())
  sword.set_linear_velocity(Vector2.RIGHT * 300)

  var is_immobile := func() -> bool: return sword.get_linear_velocity().is_zero_approx()
  await wait_until(is_immobile, 5)

Bonus idea: wait until freed

Here's a PR I made for wait_until_freed. Another way to wait until something is freed could be done with GUT just providing a predicate to check if something is freed.

func test_when_enemy_collides_with_sword_then_it_dies() -> void:
  enemy= add_child_autofree(EnemyScene.instantiate())
  enemy.set_position(Vector2.RIGHT * 100)
  sword.set_linear_velocity(Vector2.RIGHT * 300)
  sword = add_child_autofree(SwordScene.instantiate())

  var is_dead := func() -> bool: return is_object_freed(enemy) # is_object_freed being a new predicate provided by GUT
  await wait_until(is_dead , 5)