Nsubstitute：收到检查错误的方法答案

【问题标题】：Nsubstitute: Received checks wrong methodNsubstitute：收到检查错误的方法
【发布时间】：2016-07-22 07:01:19
【问题描述】：

我有一个测试，其中 NSubstitute 在假课程中检查错误的调用。当我像下面的代码一样进行测试时，Received(...) 方法会检查 factory.featureClassName 的值是否返回一次。

[Test]
public void CreateDataController_WhenCalled_CreatesServiceSettings()
{
    var factory = Substitute.ForPartsOf<AbstractDataServiceFactoryFake>("fileName");

    factory.CreateDataController();

    factory.Received(1).CreateServiceSettings("fileName", factory.FeatureClassName);
}

为了测试（如预期的那样）方法 CreateServiceSettings(...) 在我必须使用以下代码时被调用：

[Test]
public void CreateDataController_WhenCalled_CreatesServiceSettings()
{
    var factory = Substitute.ForPartsOf<AbstractDataServiceFactoryFake>("fileName");
    var featureClassName = factory.FeatureClassName;

    factory.CreateDataController();

    factory.Received(1).CreateServiceSettings("fileName", featureClassName);
}

看来，Recieved() 方法并没有直接连接到调用后给出的方法。谁能解释一下，为什么会这样？

【问题讨论】：

标签： c# testing nunit nsubstitute

【解决方案1】：

这是 NSubstitute 语法的限制。

让我们分解第二个代码示例发生的情况：

factory
    .Received(1)    // ... check the next call has previously been received
    .CreateServiceSettings("fileName", className) 
                    // call is made to CreateServiceSettings, NSub checks
                    // it was received.

在第一个代码示例中，我们改为：

factory
    .Received(1)    // ... check the next call has previously been received
    .CreateServiceSettings("fileName", factory.FeatureClassName) 
                    // before CreateServiceSettings is invoked, its arguments
                    // must be evaluated. So factory.FeatureClassName
                    // is called next and NSubstitute checks that.

换句话说，NSubstitute 看到第二个代码示例如下：

var _ = factory.Received(1).FeatureClassName;
factory.CreateServiceSettings("fileName", _);

为避免这种情况，避免在断言（如Received）或配置（如Returns）期间调用替代是有用的。

【讨论】：