Running the tests doesn't check the result of the worker based pdf processing code. This should be the case.

expect(pageLabels).toEqual(null);
    });
    it("gets page labels", async function () {
      
      const loadingTask0 = getDocument(buildGetDocumentParams("bug793632.pdf"));
      const promise0 = loadingTask0.promise.then(function (pdfDoc) {
        return pdfDoc.getPageLabels();
      });
      
      const loadingTask1 = getDocument(buildGetDocumentParams("issue1453.pdf"));
      const promise1 = loadingTask1.promise.then(function (pdfDoc) {
        return pdfDoc.getPageLabels();
      });
      
      const loadingTask2 = getDocument(buildGetDocumentParams("rotation.pdf"));
      const promise2 = loadingTask2.promise.then(function (pdfDoc) {
        return pdfDoc.getPageLabels();
      });
      
      const loadingTask3 = getDocument(
        buildGetDocumentParams("bad-PageLabels.pdf")
      );
      const promise3 = loadingTask3.promise.then(function (pdfDoc) {
        return pdfDoc.getPageLabels();
      });
      const pageLabels = await Promise.all([
        promise0,
        promise1,
        promise2,
        promise3,