Dfyjkt

I have an ASP.NET application (a basic form where I capture some input) in VS2017.

One of the fields on the form is Mark, which is an integer.

I have the following block of code for the Mark, in my .cs file.

 [Display(Name = "Mark")]
 [Range(1, 10, ErrorMessage = "Mark must be between 1 and 10")] 
 public int Mark get; set; 

I've created a MSTest project for this application to write Unit Tests.

My question is, do you write Test Cases for this block to verify the input value is in the expected range?

If yes, how you write that?

I've started with this.

 [DataRow(0, "Mark must be between 1 and 10")]
 [DataRow(11, "Mark must be between 1 and 10")]
 [DataTestMethod]
 public void TestMark_IsMarkValid_NotValid(int mark, string expectedMsg)
 
 //Arrange
 Student testStudent = new Student();
 testStudent.Mark = mark; //this does not throw any error, although the assigned value is outside of the defined range. But it looks like the range validation only applies to the webform.

 //Act

 string actualMsg = "Mark must be between 1 and 10"; //this is not correct. I was thinking to capture in the actual result the error message yield by the Range validation, but assigning a value outside range doesn't yield any error message. 

 //Assert
 Assert.AreEqual(expectedMsg, actualMsg);
 

Now, not sure if that block should be in scope for unit testing. If it should be, I have a feeling the approach I've taken is not correct.

Any thoughts, please?

Many thanks,
Cosmin

Interesting question. I'm not certain that there is a definitively correct answer. But here are my thoughts :

1) "Mark" is a property. We don't need to unit test a property because Microsoft have already tested that properties work.

2) The attributes do not affect the property, but provide information about the property that others can use. That is why your unit test passes the test for the value. The form uses the attributes, your unit test does not. That is why your unit test can assign any value.

3) If you really want to limit the value of the variable then limit it in the Student class - either by a setter or else explicit get/set and a backing variable - you can never trust any data submitted by the browser.

4) Testing a UI is not easy. We have a test team that tests by hand. We have tried several tools but none is outstanding. Keep your business logic out of your UI and put it in business classes where it can be easily tested.

So, to answer your question, I personally would not test that the attribute functions in a unit test.

I hope that helps.