init v.1.0.0

Co-authored-by: Copilot <copilot@github.com>

crates/domain/tests/motion.rs

@@ -0,0 +1,75 @@
+mod common;
+
+use common::{
+    EDGE_ONLY, ROOMY, SNUG, TINY, advance, bottom_right, logo_sprite, scene_in, sprite_count,
+};
+
+#[test]
+fn hitting_a_corner_bursts_sparkles_at_that_corner() {
+    let mut scene = scene_in(SNUG);
+
+    advance(&mut scene, SNUG, 1);
+
+    let corner = bottom_right(SNUG);
+
+    assert!(scene.sprites().any(|sprite| sprite.position() == corner));
+    assert!(sprite_count(&scene) > 1);
+}
+
+#[test]
+fn hitting_a_single_edge_recolours_but_does_not_burst() {
+    let mut scene = scene_in(EDGE_ONLY);
+    let before = logo_sprite(&scene).color();
+
+    advance(&mut scene, EDGE_ONLY, 1);
+
+    assert_ne!(logo_sprite(&scene).color(), before);
+    assert_eq!(sprite_count(&scene), 1);
+}
+
+#[test]
+fn sparkles_expire_so_the_scene_reaches_a_steady_size() {
+    let mut scene = scene_in(SNUG);
+
+    advance(&mut scene, SNUG, 64);
+    let steady = sprite_count(&scene);
+    advance(&mut scene, SNUG, 512);
+
+    assert_eq!(sprite_count(&scene), steady);
+}
+
+#[test]
+fn the_sparkle_buffer_holds_the_worst_case_without_dropping_any() {
+    let mut scene = scene_in(SNUG);
+
+    advance(&mut scene, SNUG, 256);
+
+    assert_eq!(sprite_count(&scene), 12 * 9 + 1);
+}
+
+#[test]
+fn bounds_shrinking_below_the_logo_neither_recolours_nor_bursts() {
+    let mut scene = scene_in(ROOMY);
+    let before = logo_sprite(&scene).color();
+
+    advance(&mut scene, TINY, 64);
+
+    assert_eq!(logo_sprite(&scene).color(), before);
+    assert_eq!(sprite_count(&scene), 1);
+}
+
+#[test]
+fn the_logo_never_leaves_the_bounds() {
+    let mut scene = scene_in(ROOMY);
+
+    for _ in 0..2048 {
+        advance(&mut scene, ROOMY, 1);
+
+        let logo = logo_sprite(&scene);
+        let (position, size) = (logo.position(), logo.dimensions());
+
+        assert!(position.x() >= 0.0 && position.y() >= 0.0);
+        assert!(position.x() + size.width() as f32 <= ROOMY.width() as f32);
+        assert!(position.y() + size.height() as f32 <= ROOMY.height() as f32);
+    }
+}