如何用FluentAssertions替换Assert.Fail()

时间:2017-07-11 13:13:22

标签: c# unit-testing assertions fluent-assertions

我们目前正在转换一些使用Assert.IsTrue()Assert.AreEqual()Assert.IsNotNull()等的代码。基本单元测试断言C#库

我们希望使用FluentAssertions,例如value.Should().BeNull().

我在某些地方使用Assert.Fail()进行了一些测试。我应该用什么来有效地替换它们,因为我们想要消除每一个“断言。*”,我在FluentAssertions中找不到相应的东西?

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");
}

2 个答案:

答案 0 :(得分:4)

重组测试以使用.ShouldThrow<>断言扩展名。

[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,如果未抛出预期的异常,则断言将失败,从而停止测试用例。

您应该查看documentation on asserting exceptions以更好地了解如何使用该库。

答案 1 :(得分:2)

按照这里的例子,他只是处理了Assert.Fail - 并使用了动作和.ShouldThrow http://www.continuousimprover.com/2011/07/why-i-created-fluent-assertions-in.html