Dynamisches Objekt-Mocking mit Eigenschafts-Deskriptoren für Unittests von Next.js-Headern

export function mockNextHeaders(headerMap) {
  const originalDescriptor = Object.getOwnPropertyDescriptor(globalThis, 'Headers');
  
  const MockedHeaders = class extends Headers {
    constructor() {
      super();
      Object.entries(headerMap).forEach(([key, val]) => this.set(key, val));
    }
  };
 
  Object.defineProperty(globalThis, 'Headers', {
    value: MockedHeaders,
    configurable: true,
    writable: true
  });
 
  return () => {
    if (originalDescriptor) {
      Object.defineProperty(globalThis, 'Headers', originalDescriptor);
    } else {
      delete globalThis.Headers;
    }
  };
}