feat(core): improve in-memory validation, FatturaPA detection coverage, and published type compatibility

test/test.einvoice.ts

@@ -1,5 +1,6 @@
 import { tap, expect } from '@git.zone/tstest/tapbundle';
 import { EInvoice } from '../ts/einvoice.js';
+import { EInvoiceFormatError } from '../ts/errors.js';
 import { ValidationLevel } from '../ts/interfaces/common.js';
 import type { ExportFormat } from '../ts/interfaces/common.js';
 
@@ -217,5 +218,57 @@ tap.test('EInvoice should validate XML correctly', async () => {
   expect(result.errors).toHaveLength(0);
 });
 
+tap.test('EInvoice should validate programmatic invoices without loaded XML', async () => {
+  const emptyInvoice = new EInvoice();
+  const emptyValidation = await emptyInvoice.validate();
+
+  expect(emptyValidation.valid).toBeFalse();
+  expect(emptyValidation.errors.some(error => error.code === 'BR-01')).toBeTrue();
+  expect(emptyValidation.errors.some(error => error.code === 'BR-16')).toBeTrue();
+
+  const validInvoice = new EInvoice();
+  validInvoice.accountingDocId = 'TEST-IN-MEMORY';
+  validInvoice.from.name = 'Programmatic Seller';
+  validInvoice.from.address = {
+    streetName: 'Seller Street',
+    houseNumber: '1',
+    city: 'Berlin',
+    postalCode: '10115',
+    country: 'DE'
+  };
+  validInvoice.to.name = 'Programmatic Buyer';
+  validInvoice.to.address = {
+    streetName: 'Buyer Street',
+    houseNumber: '2',
+    city: 'Hamburg',
+    postalCode: '20095',
+    country: 'DE'
+  };
+  validInvoice.items.push({
+    position: 1,
+    name: 'Programmatic Product',
+    articleNumber: 'PP-001',
+    unitType: 'EA',
+    unitQuantity: 1,
+    unitNetPrice: 100,
+    vatPercentage: 19
+  });
+
+  const validResult = await validInvoice.validate(ValidationLevel.BUSINESS);
+  expect(validResult.valid).toBeTrue();
+  expect(validResult.errors).toHaveLength(0);
+});
+
+tap.test('EInvoice should reject unsupported invoice types explicitly', async () => {
+  const einvoice = new EInvoice();
+
+  try {
+    einvoice.invoiceType = 'creditnote';
+    expect(true).toBeFalse();
+  } catch (error) {
+    expect(error).toBeInstanceOf(EInvoiceFormatError);
+  }
+});
+
 // Run the tests
 tap.start();