time for a snapshot

workshop/steps/10-move-and-slide/moveAndSlide.test.ts

@@ -0,0 +1,37 @@
+import { expect, test } from "bun:test";
+import { type AABB, vec } from "./given.ts";
+import { moveAndSlide } from "./moveAndSlide.ts";
+
+const player: AABB = { x: 0, y: 0, w: 2, h: 2 };
+
+test("no walls -> full move", () => {
+	const p = moveAndSlide(player, vec(10, 5), []);
+	expect(p.x).toBeCloseTo(10);
+	expect(p.y).toBeCloseTo(5);
+});
+
+test("head-on into the NEAREST of two walls -> stops there", () => {
+	const walls: AABB[] = [
+		{ x: 5, y: 0, w: 2, h: 2 }, // nearer
+		{ x: 8, y: 0, w: 2, h: 2 }, // farther
+	];
+	const p = moveAndSlide(player, vec(10, 0), walls);
+	expect(p.x).toBeCloseTo(3); // right edge (2) meets wall left edge (5)
+	expect(p.y).toBeCloseTo(0);
+});
+
+test("diagonal into a vertical wall -> slides down it", () => {
+	// x is blocked at 3, but the downward motion keeps going for the whole frame
+	const walls: AABB[] = [{ x: 5, y: -10, w: 2, h: 40 }];
+	const p = moveAndSlide(player, vec(10, 10), walls);
+	expect(p.x).toBeCloseTo(3);
+	expect(p.y).toBeCloseTo(10);
+});
+
+test("diagonal onto a floor -> slides along it", () => {
+	// falls until its bottom meets the floor top (y=8 -> corner y=6), keeps moving in x
+	const walls: AABB[] = [{ x: 0, y: 8, w: 20, h: 2 }];
+	const p = moveAndSlide(player, vec(5, 10), walls);
+	expect(p.x).toBeCloseTo(5);
+	expect(p.y).toBeCloseTo(6);
+});