Test/unit test generateinvoice file generation libinvoicets

tests/unit/invoice.test.ts

@@ -0,0 +1,132 @@
+import {
+  existsSync,
+  mkdirSync,
+  mkdtempSync,
+  readdirSync,
+  readFileSync,
+  rmSync,
+  writeFileSync,
+} from "fs";
+import os from "os";
+import path from "path";
+import { PDFDocument, PDFPage } from "pdf-lib";
+import { generateInvoice } from "../../lib/invoice";
+
+const item = { name: "Test Product", quantity: 1, priceAtPurchase: 10 };
+
+const invoiceData = {
+  orderId: "ORD-001",
+  createdAt: new Date(2026, 9, 30),
+  customerName: "Test Customer",
+  customerEmail: "test@example.com",
+  address: {
+    street: "123 Test Street",
+    city: "Test City",
+    state: "TS",
+    zipCode: "12345",
+    country: "Test Country",
+  },
+  items: [item],
+  total: 10,
+};
+
+describe("generateInvoice", () => {
+  let workDir: string;
+  let invoicesDir: string;
+  let drawText: jest.SpyInstance;
+
+  const printedText = () => drawText.mock.calls.map(([text]) => text);
+
+  beforeEach(() => {
+    workDir = mkdtempSync(path.join(os.tmpdir(), "oopssec-invoice-"));
+    invoicesDir = path.join(workDir, "documents", "invoices");
+    jest.spyOn(process, "cwd").mockReturnValue(workDir);
+    drawText = jest.spyOn(PDFPage.prototype, "drawText");
+  });
+
+  afterEach(() => {
+    jest.restoreAllMocks();
+    rmSync(workDir, { recursive: true, force: true });
+  });
+
+  it("stores the invoice as documents/invoices/invoice-<orderId>.pdf under the working directory, creating the folder", async () => {
+    const filepath = await generateInvoice(invoiceData);
+
+    expect(filepath).toBe(path.join(invoicesDir, "invoice-ORD-001.pdf"));
+    expect(existsSync(filepath)).toBe(true);
+  });
+
+  it("keeps the files already stored in the invoices folder", async () => {
+    mkdirSync(invoicesDir, { recursive: true });
+    writeFileSync(path.join(invoicesDir, "invoice-older.pdf"), "older");
+
+    await generateInvoice(invoiceData);
+
+    expect(readdirSync(invoicesDir).sort()).toEqual([
+      "invoice-ORD-001.pdf",
+      "invoice-older.pdf",
+    ]);
+    expect(
+      readFileSync(path.join(invoicesDir, "invoice-older.pdf"), "utf8")
+    ).toBe("older");
+  });
+
+  it("writes a single-page PDF", async () => {
+    const filepath = await generateInvoice(invoiceData);
+
+    const pdf = await PDFDocument.load(readFileSync(filepath));
+    expect(pdf.getPageCount()).toBe(1);
+  });
+
+  it("prints an item name of 40 characters in full", async () => {
+    const name = "x".repeat(40);
+
+    await generateInvoice({ ...invoiceData, items: [{ ...item, name }] });
+
+    expect(printedText()).toContain(name);
+  });
+
+  it("cuts an item name longer than 40 characters to 40 and appends an ellipsis", async () => {
+    const name = "x".repeat(40) + "y";
+
+    await generateInvoice({ ...invoiceData, items: [{ ...item, name }] });
+
+    expect(printedText()).toContain(`${"x".repeat(40)}...`);
+    expect(printedText()).not.toContain(name);
+  });
+
+  // Local-time inputs keep the expected label independent of the machine's time zone.
+  it.each([
+    ["a Date", new Date(2026, 9, 30, 10)],
+    ["a string", "2026-10-30T10:00:00"],
+  ])(
+    "prints the order date in long US format when createdAt is %s",
+    async (_, createdAt) => {
+      await generateInvoice({ ...invoiceData, createdAt });
+
+      expect(printedText()).toContain("Date: October 30, 2026");
+    }
+  );
+
+  it("prints unit prices, line totals and the order total with two decimals", async () => {
+    await generateInvoice({
+      ...invoiceData,
+      items: [
+        { name: "Sticker", quantity: 3, priceAtPurchase: 2.5 },
+        { name: "Mug", quantity: 1, priceAtPurchase: 12 },
+      ],
+      total: 19.5,
+    });
+
+    expect(printedText()).toEqual(
+      expect.arrayContaining(["$2.50", "$7.50", "$12.00", "$19.50"])
+    );
+  });
+
+  it("rejects when the invoice cannot be written", async () => {
+    mkdirSync(path.dirname(invoicesDir));
+    writeFileSync(invoicesDir, "");
+
+    await expect(generateInvoice(invoiceData)).rejects.toThrow();
+  });
+});