如何用FluentAssertions替换Assert.Fail（）

Question

目前，我们正在将使用一些代码Assert.IsTrue()，Assert.AreEqual()，Assert.IsNotNull()，等的基本单元测试断言库C＃

我们要使用FluentAssertions，例如 value.Should().BeNull().

我Assert.Fail()在某些地方使用了一些测试。我想用什么来有效地替换那些，因为我们要删除每个“ Assert。*”，而我在FluentAssertions中找不到等效的东西？

这是一个例子

[TestMethod, TestCategory("ImportantTest")]
public void MethodToTest_Circumstances_ExpectedResult()
{
    // Arrange
    var variable1 = new Type1() { Value = "hello" };
    var variable2 = new Type2() { Name = "Bob" };

    // Act
    try
    {
        MethodToTest(variable1, variable2);
        // This method should have thrown an exception
        Assert.Fail();
    }
    catch (Exception ex)
    {
        ex.Should().BeOfType<DataException>();
        ex.Message.Should().Be(Constants.DataMessageForMethod);
    }

    // Assert
    // test that variable1 was changed by the method
    variable1.Should().NotBeNull();
    variable1.Value.Should().Be("Hello!");
    // test that variable2 is unchanged because the method threw an exception before changing it
    variable2.Should().NotBeNull();
    variable2.Name.Should().Be("Bob");
}

Answer 1

重组测试以利用.ShouldThrow<>断言扩展。

[TestMethod, TestCategory("ImportantTest")]
public void MethodToTest_Circumstances_ExpectedResult() {
    // Arrange
    var variable1 = new Type1() { Value = "hello" };
    var variable2 = new Type2() { Name = "Bob" };

    // Act
    Action act = () => MethodToTest(variable1, variable2);       

    // Assert
    // This method should have thrown an exception
    act.ShouldThrow<DataException>()
       .WithMessage(Constants.DataMessageForMethod);
    // test that variable1 was changed by the method
    variable1.Should().NotBeNull();
    variable1.Value.Should().Be("Hello!");
    // test that variable2 is unchanged because the method threw an exception before changing it
    variable2.Should().NotBeNull();
    variable2.Name.Should().Be("Bob");
}

在上面的示例中，如果未引发预期的异常，则断言将失败，从而停止测试用例。

您应该查看有关声明异常的文档，以更好地了解如何使用该库。