c# - 创建对象的单元测试方法，麻烦断言

Question

我有一个方法，它接受一个 XML 字符串并对其进行解析，返回一个IEnumerable<Invoice>. 以下是正在使用的类的定义。请注意，anInvoice包含InvoiceItems：

public class Invoice
{
    public const string XmlName = "invoice";

    public int id { get; set; }
    public string title { get; set; }
    public DateTime timestamp { get; set; }
    public bool paid { get; set; }
    public IList<InvoiceItem> items { get; set; }

    public Invoice() { this.items = new List<InvoiceItem>(); }

    public decimal getTotal()
    {
        if (items == null)
            return 0;

        decimal total = 0;

        foreach (InvoiceItem item in this.items)
            total += item.amount;

        return total;
    }
}

public class InvoiceItem
{
    public const string XmlName = "item";

    public string description { get; set; }
    public decimal amount { get; set; }
}

当使用 NUnit 对方法进行单元测试时，布尔值会发生一些奇怪的事情paid。请注意，我已经在 .NET Fiddle 中测试了该方法，它返回了它应该返回的所有对象。因此，以下测试（部分代码）似乎有问题：

[Test]
public void readXml_Test()
{
    // arrange

    // xml stuff...

    // expected objects
    InvoiceItem item1 = new InvoiceItem { description = "item 1 in invoice 1", amount = 50 };
    InvoiceItem item2 = new InvoiceItem { description = "item 2 in invoice 1", amount = 50 };
    Invoice invoice1 = new Invoice
    {
        id = 1,
        title = "Aug 2020",
        timestamp = DateTime.ParseExact("16/08/2020 09:01:29 AM", "dd/MM/yyyy hh:mm:ss tt", System.Globalization.CultureInfo.InvariantCulture),
        paid = true,
        items = new List<InvoiceItem>() { item1, item2 }
     };
     InvoiceItem item3 = new InvoiceItem { description = "item in invoice 2", amount = 100 };
     Invoice invoice2 = new Invoice
     {
         id = 2,
         title = "Sep 2020",
         timestamp = DateTime.ParseExact("16/08/2020 09:01:29 AM", "dd/MM/yyyy hh:mm:ss tt", System.Globalization.CultureInfo.InvariantCulture),
         paid = true,
         items = new List<InvoiceItem> { item3 }
      };

    // act
    List<Invoice> actual = xml.readXml().ToList(); // readXml() is the method under test.

    // assert
    Assert.That(actual.Contains(invoice1));
    Assert.That(actual.Contains(invoice2));
}

如前所述，我在 .NET fiddle 中对此进行了测试，结果对象都具有正确的属性值。但是，上述测试产生：

Message: Expected: True
 But was: False

没有提到任何例外。因为我知道被测方法有效，所以这个测试似乎有问题。我该如何解决它以使其通过？

标签： c#.netunit-testingnunitassert