CODEWITHSUNDEEP
asp.netunit-testing
espenk
espenk

Reputation: 585

asp.net write unit test that returns Exception

I have a Repositry class wich initiates like this:

public ContactRepository(string sqlStr, string username)
{
    if (!string.IsNullOrEmpty(sqlStr))
    {
        ent = new AceoEntities(sqlStr);
        Username = username; 
    }
    else
        new Exception("No sql string is defined");
}

This might not be the best method, but I would like to make sure it's not possible to create an instance off the class without sqlStr.

Then I'm trying to test this:

[TestMethod()]
public void CreateContactRepositoryWithEmtySqlString()
{
    string sqlStr = string.Empty;
    ContactRepository target;

    try
    {
        target = new ContactRepository("kvelland-kk", sqlStr);
    }
    catch (Exception e)
    {
        Assert.AreEqual("No sql string is defined",e.Message);
    }
}

My question is: Is this the correct way to to this? I' having problems getting this to work.

Upvotes: 1

Views: 716

Answers (3)

GarethOwen
GarethOwen

Reputation: 6133

I would rather use the ExpectedException attribute to mark your TestMethod, and throw a more specific type of exception, for example an ArgumentException:

[TestMethod()]
[ExpectedException(typeof(System.ArgumentException))]
public void CreateContactRepositoryWithEmtySqlString()
{
    ContactRepository target = new ContactRepository("kvelland-kk", string.Empty);
}

Upvotes: 3

lahsrah
lahsrah

Reputation: 9173

I prefer GarethOwen's answer (the ExpectedException attribute) or this way:

public void MyTest()
{
    try
    {    
        target = new ContactRepository("kvelland-kk", sqlStr); 

        Assert.Fail("Should have failed with MyExceptionType");
    }
    catch(MyExceptionType){}
}

Checking exception messages is not a good idea. Cause you may get a different message based on the system localisation. Check for the exception type instead. And as Xhalent mentioned don't throw the a Exception, throw a specific type of exception.

Upvotes: 0

Xhalent
Xhalent

Reputation: 3954

you forgot the throw the new Exception

throw new Exception("No sql string is defined");

Interestingly, this kind of demonstrates the value of unit tests, as they have shown up a simple coding error easily over looked.

Upvotes: 0

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