added api logic, vitest, minimal testing ui

api/tests/income.test.ts

@@ -0,0 +1,61 @@
+// tests/income.test.ts
+import request from "supertest";
+import { describe, it, expect, beforeEach, afterAll, beforeAll } from "vitest";
+import appFactory from "./appFactory";
+import { prisma, resetUser, ensureUser, U, cid, pid, closePrisma } from "./helpers";
+import type { FastifyInstance } from "fastify";
+
+let app: FastifyInstance;
+
+beforeAll(async () => {
+  app = await appFactory();            // <-- await the app
+});
+
+afterAll(async () => {
+  await app.close();                   // <-- close server
+  await closePrisma();
+});
+
+describe("POST /income", () => {
+  beforeEach(async () => {
+    await resetUser(U);
+    await ensureUser(U);
+
+    await prisma.variableCategory.createMany({
+      data: [
+        { id: cid("c1"), userId: U, name: "Groceries", percent: 60, priority: 2, isSavings: false, balanceCents: 0n },
+        { id: cid("c2"), userId: U, name: "Saver",     percent: 40, priority: 1, isSavings: true,  balanceCents: 0n },
+      ],
+    });
+
+    await prisma.fixedPlan.create({
+      data: {
+        id: pid("rent"),
+        userId: U,
+        name: "Rent",
+        cycleStart: new Date().toISOString(),
+        dueOn: new Date(Date.now() + 7 * 864e5).toISOString(),
+        totalCents: 10000n,
+        fundedCents: 0n,
+        priority: 1,
+        fundingMode: "auto-on-deposit",
+      },
+    });
+  });
+
+  afterAll(async () => {
+    await closePrisma();
+  });
+
+  it("allocates fixed first then variables; updates balances; returns audit", async () => {
+    const res = await request(app.server)
+      .post("/income")
+      .set("x-user-id", U)
+      .send({ amountCents: 15000 });
+
+    expect(res.statusCode).toBe(200);
+    expect(res.body).toHaveProperty("fixedAllocations");
+    expect(res.body).toHaveProperty("variableAllocations");
+    expect(typeof res.body.remainingUnallocatedCents).toBe("number");
+  });
+});