高階約束使用

大的流暢斷言確實變得難以閱讀，但是當與具有良好實現 ToString() 的類組合時，它們可以生成非常有用的錯誤訊息。

[Test]
public void AdvancedContraintsGiveUsefulErrorMessages() {
    Assert.That(actualCollection, Has
        .Count.EqualTo(4)
        .And.Exactly(1).Property("Age").GreaterThan(60)
        .And.Some.Property("Address").Null
        .And.No.Property("Age").LessThanOrEqualTo(17));
}

失敗時，此斷言會生成如下訊息：

Expected: property Count equal to 4 and exactly one item property Age greater
than 60 and some item property Address null and not property Age less than or
equal to 17
But was:  < <Steve Taylor (23) lives in Newcastle
>, <Michelle Yung (65) lives in San Francisco
>, <Ranjit Saraman (49) lives in Milano
>, <LaChelle Oppenheimer (16) lives in 
> >