test(suite): comprehensive test suite improvements and new validators

- Update test-utils import path and refactor to helpers/utils.ts
- Migrate all CorpusLoader usage from getFiles() to loadCategory() API
- Add new EN16931 UBL validator with comprehensive validation rules
- Add new XRechnung validator extending EN16931 with German requirements
- Update validator factory to support new validators
- Fix format detector for better XRechnung and EN16931 detection
- Update all test files to use proper import paths
- Improve error handling in security tests
- Fix validation tests to use realistic thresholds
- Add proper namespace handling in corpus validation tests
- Update format detection tests for improved accuracy
- Fix test imports from classes.xinvoice.ts to index.js

All test suites now properly aligned with the updated APIs and realistic performance expectations.

ts/formats/factories/validator.factory.ts

@@ -4,137 +4,13 @@ import type { ValidationResult } from '../../interfaces/common.js';
 import { FormatDetector } from '../utils/format.detector.js';
 
 // Import specific validators
-import { UBLBaseValidator } from '../ubl/ubl.validator.js';
+import { EN16931UBLValidator } from '../ubl/en16931.ubl.validator.js';
+import { XRechnungValidator } from '../ubl/xrechnung.validator.js';
 import { FacturXValidator } from '../cii/facturx/facturx.validator.js';
 import { ZUGFeRDValidator } from '../cii/zugferd/zugferd.validator.js';
 
-/**
- * UBL validator implementation
- * Provides validation for standard UBL documents
- */
-class UBLValidator extends UBLBaseValidator {
-  protected validateStructure(): boolean {
-    // Basic validation to check for required UBL invoice elements
-    if (!this.doc) return false;
-
-    let valid = true;
-
-    // Check for required UBL elements
-    const requiredElements = [
-      'cbc:ID',
-      'cbc:IssueDate',
-      'cac:AccountingSupplierParty',
-      'cac:AccountingCustomerParty'
-    ];
-
-    for (const element of requiredElements) {
-      if (!this.exists(`//${element}`)) {
-        this.addError(
-          'UBL-STRUCT-1',
-          `Required element ${element} is missing`,
-          `/${element}`
-        );
-        valid = false;
-      }
-    }
-
-    return valid;
-  }
-
-  protected validateBusinessRules(): boolean {
-    // Basic business rule validation for UBL
-    if (!this.doc) return false;
-
-    let valid = true;
-
-    // Check that issue date is present and valid
-    const issueDateText = this.getText('//cbc:IssueDate');
-    if (!issueDateText) {
-      this.addError(
-        'UBL-BUS-1',
-        'Issue date is required',
-        '//cbc:IssueDate'
-      );
-      valid = false;
-    } else {
-      const issueDate = new Date(issueDateText);
-      if (isNaN(issueDate.getTime())) {
-        this.addError(
-          'UBL-BUS-2',
-          'Issue date is not a valid date',
-          '//cbc:IssueDate'
-        );
-        valid = false;
-      }
-    }
-
-    // Check that at least one invoice line exists
-    if (!this.exists('//cac:InvoiceLine') && !this.exists('//cac:CreditNoteLine')) {
-      this.addError(
-        'UBL-BUS-3',
-        'At least one invoice line or credit note line is required',
-        '/'
-      );
-      valid = false;
-    }
-
-    return valid;
-  }
-}
-
-/**
- * XRechnung validator implementation
- * Extends UBL validator with additional XRechnung specific validation rules
- */
-class XRechnungValidator extends UBLValidator {
-  protected validateStructure(): boolean {
-    // Call the base UBL validation first
-    const baseValid = super.validateStructure();
-    let valid = baseValid;
-
-    // Check for XRechnung-specific elements
-    if (!this.exists('//cbc:CustomizationID[contains(text(), "xrechnung")]')) {
-      this.addError(
-        'XRECH-STRUCT-1',
-        'XRechnung customization ID is missing or invalid',
-        '//cbc:CustomizationID'
-      );
-      valid = false;
-    }
-
-    // Check for buyer reference which is mandatory in XRechnung
-    if (!this.exists('//cbc:BuyerReference')) {
-      this.addError(
-        'XRECH-STRUCT-2',
-        'BuyerReference is required in XRechnung',
-        '//'
-      );
-      valid = false;
-    }
-
-    return valid;
-  }
-
-  protected validateBusinessRules(): boolean {
-    // Call the base UBL business rule validation
-    const baseValid = super.validateBusinessRules();
-    let valid = baseValid;
-
-    // German-specific validation rules
-    // Check for proper VAT ID structure for German VAT IDs
-    const supplierVatId = this.getText('//cac:AccountingSupplierParty//cbc:CompanyID[../cac:TaxScheme/cbc:ID="VAT"]');
-    if (supplierVatId && supplierVatId.startsWith('DE') && !/^DE[0-9]{9}$/.test(supplierVatId)) {
-      this.addError(
-        'XRECH-BUS-1',
-        'German VAT ID format is invalid (must be DE followed by 9 digits)',
-        '//cac:AccountingSupplierParty//cbc:CompanyID'
-      );
-      valid = false;
-    }
-
-    return valid;
-  }
-}
+// The EN16931UBLValidator handles all UBL-based formats with proper business rules
+// No need for legacy validator implementations here
 
 /**
  * FatturaPA validator implementation
@@ -191,7 +67,7 @@ export class ValidatorFactory {
 
       switch (format) {
         case InvoiceFormat.UBL:
-          return new UBLValidator(xml);
+          return new EN16931UBLValidator(xml);
 
         case InvoiceFormat.XRECHNUNG:
           return new XRechnungValidator(xml);