单位测试属性的主体

Question

This is my Code

public class AssistanceRequest : DocumentBase
{
    public AssistanceRequest()
    {
        RequestTime = DateTime.Now;
        ExcecutionTime = DateTime.MaxValue;
    }

    public AssistanceRequest(int amount, string description, DateTime? requestTime) : this()
    {
        //Check for basic validations
        if (amount <= 0)
            throw new Exception("Amount is not Valid");
        this.Amount = amount;
        this.Description = description;
        this.RequestTime = requestTime ?? DateTime.Now;
    }

    private long Amount { get; set; }

    private DateTime requestTime { get; set; }

    public DateTime RequestTime
    {
        get { return requestTime; }
        set
        {
            if (value != null && value < DateTime.Now)
                throw new Exception("Request Time is not Allowed");
            requestTime = value;
        }
    }

As you can see I have a validation in my Set body. I need to test it. and I try to call the constructor in my Tests. but I get Exception in Constructor ( act ) before assertion. How to make my tests right?

This is my Test:

[Theory]
    [MemberData("RequestFakeData")]
    public void Should_Throw_Exception_RequestDate(int amount, string description, DateTime requestDate)
    {
        var manager = new AssistanceRequest(amount,description,requestDate);
        manager.Invoking(x => x.SomeMethodToChangeRequestTime).ShouldThrowExactly<Exception>()
    }

    public static IEnumerable<object[]> RequestFakeData
    {
        get
        {
            // Or this could read from a file. :)
            return new[]
            {
            new object[] { 0,string.Empty,DateTime.Now.AddDays(1) },
            new object[] { 2,"",DateTime.Now.AddDays(-2) },
            new object[] { -1,string.Empty,DateTime.Now.AddDays(-3) },
            };
        }
    }

I get the Error in about this Line:

var manager = new AssistanceRequest(amount,description,requestDate);

the constructor is trying to set the property so it gets the Exception. and does not get to the assertion.

My question is: How can I test this without changing my constructor?

Answer 1

I found the solution and for those who check later on I put it right here.

If we want to test these types of Exceptions in xUnit it may get a little tricky.

I read an article here: http://hadihariri.com/2008/10/17/testing-exceptions-with-xunit/

it helped me out to edit my Code and get the right answer.

I changed my Tests like this:

[Theory]
    [MemberData("RequestFakeData")]
    public void Should_Throw_Exception_RequestDate(int amount, string description, DateTime requestDate)
    {
        Exception ex = Assert.Throws<Exception>(() => new AssistanceRequest(amount,description,requestDate));
        Assert.Equal("Request Time is not Allowed",ex.Message);
    }

    public static IEnumerable<object[]> RequestFakeData
    {
        get
        {
            return new[]
            {
            new object[] { 1,string.Empty,DateTime.Now },
            new object[] { 2,"",DateTime.Now.AddDays(-2) },
            new object[] { 1,string.Empty,DateTime.Now.AddDays(-3) },
            };
        }
    }

hope it would be helpful.

Answer 2

I'm not familiar with XUnit syntax but I would think you need to remove the "manager.Invoking" line as the exception will be thrown on the line above, then replace it with an ExpectedException attribute on the test itself.

Something like:

[ExpectedException(typeof(Exception))]
[MemberData("RequestFakeData")]
public void Should_Throw_Exception_RequestDate......

Additionally, I'd recommend switching Exception for ArgumentException.

Edit: I can't be sure if the below syntax is correct on the lambda statement, but this should be a good start.

[MemberData("RequestFakeData")]
public void Should_Throw_Exception_RequestDate(int amount, string description, DateTime requestDate)
{
    Exception ex = Assert.Throws<Exception>(() => new AssistanceRequest(amount,description,requestDate));

    Assert.Equal("Request Time is not Allowed", ex.Message)
}

I extrapolated this answer from: http://hadihariri.com/2008/10/17/testing-exceptions-with-xunit/