public async Task PO05_GetAllPurchaseOrdersTest()
        {
            // Arrange
            List <PurchaseOrder> poList;

            // Act
            poList = await PurchaseOrderController.GetAll(_authToken);

            // Assert
            Assert.IsNotNull(poList, "Expected a List<PurchaseOrder>, got null");
            Assert.IsTrue(poList.Count >= 1, "Expected at least one member of this list, got " + poList.Count);
            Assert.IsTrue(poList.Contains(_purchaseOrder), "List does not contain the test PurchaseOrder");
        }