feat(frontend): constellation lib scaffold — graph/layout/camera pure modules (tested)

services/frontend/src/lib/constellation/camera.test.ts

@@ -0,0 +1,49 @@
+import { describe, expect, test } from "bun:test";
+import { fitCamera, flyTo } from "./camera";
+
+describe("flyTo", () => {
+  const from = { x: 0, y: 0, z: 1 };
+  const to = { x: 100, y: -50, z: 2 };
+
+  test("t=0 returns origin", () => {
+    expect(flyTo(from, to, 0)).toEqual({ x: 0, y: 0, z: 1 });
+  });
+
+  test("t=1 arrives exactly", () => {
+    expect(flyTo(from, to, 1)).toEqual(to);
+  });
+
+  test("monotonic progress", () => {
+    let prev = -Infinity;
+    for (let i = 0; i <= 20; i++) {
+      const s = flyTo(from, to, i / 20);
+      expect(s.x).toBeGreaterThan(prev);
+      prev = s.x;
+    }
+  });
+
+  test("clamps out-of-range t", () => {
+    expect(flyTo(from, to, -3)).toEqual(from);
+    expect(flyTo(from, to, 7)).toEqual(to);
+  });
+});
+
+describe("fitCamera", () => {
+  test("empty scene centers", () => {
+    const c = fitCamera([], 800, 600);
+    expect(c.x).toBe(400);
+    expect(c.y).toBe(300);
+  });
+
+  test("zooms to fit nodes with padding", () => {
+    const nodes = [
+      { x: 100, y: 100, r: 10 },
+      { x: 500, y: 400, r: 10 },
+    ];
+    const c = fitCamera(nodes, 800, 600);
+    expect(c.x).toBe(300);
+    expect(c.y).toBe(250);
+    expect(c.z).toBeGreaterThan(0);
+    expect(c.z).toBeLessThanOrEqual(3);
+  });
+});