time for a snapshot

workshop/steps/01-vectors/vector.test.ts

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+import { expect, test } from "bun:test";
+import { add, scale, sub, vec } from "./vector.ts";
+
+test("vec builds a vector", () => {
+	expect(vec(2, 3)).toEqual({ x: 2, y: 3 });
+});
+
+test("add is component-wise", () => {
+	expect(add(vec(1, 2), vec(3, 4))).toEqual({ x: 4, y: 6 });
+});
+
+test("sub is component-wise", () => {
+	expect(sub(vec(5, 5), vec(1, 2))).toEqual({ x: 4, y: 3 });
+});
+
+test("scale multiplies both components", () => {
+	expect(scale(vec(2, 3), 2)).toEqual({ x: 4, y: 6 });
+	expect(scale(vec(2, 3), 0)).toEqual({ x: 0, y: 0 });
+});
+
+test("inputs are not mutated (pure functions)", () => {
+	const a = vec(1, 2);
+	add(a, vec(3, 4));
+	expect(a).toEqual({ x: 1, y: 2 });
+});