bevy/tests/how_to_test_systems.rs
Daniel McNab c26be39719 Remove unnecessary system labels (#4340)
# Objective

- Since #4224, using labels which only refer to one system doesn't make sense.

## Solution

- Remove some of those.

## Future work

- We should remove the ability to use strings as system labels entirely. I haven't in this PR because there are tests which use this, and that's a lot of code to change.
   - The only use cases for labels are either intra-crate, which use #4224, or inter-crate, which should either use #4224 or explicit types. Neither of those should use strings.
2022-04-01 21:11:05 +00:00

97 lines
2.6 KiB
Rust

use bevy::prelude::*;
#[derive(Component, Default)]
struct Enemy {
hit_points: u32,
}
fn despawn_dead_enemies(mut commands: Commands, enemies: Query<(Entity, &Enemy)>) {
for (entity, enemy) in enemies.iter() {
if enemy.hit_points == 0 {
commands.entity(entity).despawn_recursive();
}
}
}
fn hurt_enemies(mut enemies: Query<&mut Enemy>) {
for mut enemy in enemies.iter_mut() {
enemy.hit_points -= 1;
}
}
fn spawn_enemy(mut commands: Commands, keyboard_input: Res<Input<KeyCode>>) {
if keyboard_input.just_pressed(KeyCode::Space) {
commands.spawn().insert(Enemy { hit_points: 5 });
}
}
#[test]
fn did_hurt_enemy() {
// Setup world
let mut world = World::default();
// Setup stage with our two systems
let mut update_stage = SystemStage::parallel();
update_stage.add_system(hurt_enemies.before(despawn_dead_enemies));
update_stage.add_system(despawn_dead_enemies);
// Setup test entities
let enemy_id = world.spawn().insert(Enemy { hit_points: 5 }).id();
// Run systems
update_stage.run(&mut world);
// Check resulting changes
assert!(world.get::<Enemy>(enemy_id).is_some());
assert_eq!(world.get::<Enemy>(enemy_id).unwrap().hit_points, 4);
}
#[test]
fn did_despawn_enemy() {
// Setup world
let mut world = World::default();
// Setup stage with our two systems
let mut update_stage = SystemStage::parallel();
update_stage.add_system(hurt_enemies.before(despawn_dead_enemies));
update_stage.add_system(despawn_dead_enemies);
// Setup test entities
let enemy_id = world.spawn().insert(Enemy { hit_points: 1 }).id();
// Run systems
update_stage.run(&mut world);
// Check resulting changes
assert!(world.get::<Enemy>(enemy_id).is_none());
}
#[test]
fn spawn_enemy_using_input_resource() {
// Setup world
let mut world = World::default();
// Setup stage with a system
let mut update_stage = SystemStage::parallel();
update_stage.add_system(spawn_enemy);
// Setup test resource
let mut input = Input::<KeyCode>::default();
input.press(KeyCode::Space);
world.insert_resource(input);
// Run systems
update_stage.run(&mut world);
// Check resulting changes, one entity has been spawned with `Enemy` component
assert_eq!(world.query::<&Enemy>().iter(&world).len(), 1);
// Clear the `just_pressed` status for all `KeyCode`s
world.resource_mut::<Input<KeyCode>>().clear();
// Run systems
update_stage.run(&mut world);
// Check resulting changes, no new entity has been spawned
assert_eq!(world.query::<&Enemy>().iter(&world).len(), 1);
}