如何在C＃中对KnockoutUtility进行单元测试？

Question

I have a class that gets knockout messages using the method below:

public IEnumerable<Message> GetKnockoutMessages(Data data)
    {
        if(data.Messages != null)
        {
            return data.Messages.Where(m => m.UnderWritingRuleId != null);
        }
        else
        {
            return new List<Message>();
        }
    }

So far, i have a unit test that only partially covers the unit test which is below.

[TestMethod]
    public void TestGetKnockoutMessages()
    {
        KnockoutUtility knockUtility = new KnockoutUtility();
        IEnumerable<Message> messages = knockUtility.GetKnockoutMessages(MockData.Object);
        Assert.IsNotNull(messages);
    }

This covers everything but return data.Messages.Where(m => m.UnderWritingRuleId != null);

I was wondering how I would unit test this method to get 100% coverage.

Any help would be appreciated. Thanks

Answer 1

This unit test doesn't cover everything because you are not verifying all cases. You have to test two logics:

• if/else logic
• Where(m => m.UnderWritingRuleId != null) logic

Based on this assumption you have to create cases which proof following:

• If data.Messages are null then you have to verify that method returns new instance of List<Message>() because you specified in code like that.
• Next case will be to verify that method returns empty IEnumerable<Message> if data.Messages are empty (which means this condition data.Messages.Count() == 0 ).
• Next case will be to verify that method returns exact messages which satisfied your condition: Where(m => m.UnderWritingRuleId != null) . In other words only messages which have populated UnderWritingRuleId .

To achieve what I mentioned you have to create Data objects which satisfied this cases. I don't know what is MockData.Object but I hope that you included you arrangement there.

Each case should be in separate test method like in following:

[TestMethod]
public void TestGetKnockoutMessages_Case1()
{
     // Arrange

     // Action

     // Assert
}

[TestMethod]
public void TestGetKnockoutMessages_Case2()
{
     // Arrange

     // Action

     // Assert
}

[TestMethod]
public void TestGetKnockoutMessages_Case3()
{
     // Arrange

     // Action

     // Assert
}

Arrange is place where you configuring your mock-ups. Action is place where you executing method which you want to test and Assert is place where you doing assertion.