Refactorizing tests

I had read, in some place on the cloud, that SharpTestsEx make the test more verbose even if it is more readable.

In NHibernate.Validator (NHV) we are using #TestsEx. After implements some new features I’m improving some stuff where I’m needing a little breaking change.

This is an existing test using classic NUnit syntax:

[Test]
public void CreditCard()
{
   CreditCard card = new CreditCard();
   card.number = "1234567890123456";
   IClassValidator classValidator = GetClassValidator(typeof(CreditCard));
   InvalidValue[] invalidValues = classValidator.GetInvalidValues(card);
   Assert.AreEqual(1, invalidValues.Length);
   card.number = "541234567890125"; //right CC (luhn compliant)
   invalidValues = classValidator.GetInvalidValues(card);
   Assert.AreEqual(0, invalidValues.Length);
   card.ean = "9782266156066"; 
   invalidValues = classValidator.GetInvalidValues(card);
   Assert.AreEqual(0, invalidValues.Length);
   card.ean = "9782266156067"; 
   invalidValues = classValidator.GetInvalidValues(card);
   Assert.AreEqual(1, invalidValues.Length);
}

The breaking change is about the return value of GetInvalidValues : in NHV1.2.0 the method will return IEnumerable<InvalidValue>.

Refactoring step 1

Same but compileable.

[Test]
public void CreditCard()
{
   CreditCard card = new CreditCard();
   IClassValidator classValidator = GetClassValidator(typeof(CreditCard));

   card.number = "1234567890123456";
   Assert.That(classValidator.GetInvalidValues(card), Is.Not.Empty);
  
   card.number = "541234567890125"; //right CC (luhn compliant)
   Assert.That(classValidator.GetInvalidValues(card), Is.Empty);

   card.ean = "9782266156066";
   Assert.That(classValidator.GetInvalidValues(card), Is.Empty);

   card.ean = "9782266156067";
   Assert.That(classValidator.GetInvalidValues(card), Is.Not.Empty);
}

Refactoring step 2

[Test]
public void CreditCard()
{
   CreditCard card = new CreditCard();
   var classValidator = GetClassValidator(typeof(CreditCard));

   card.number = "1234567890123456";
   classValidator.GetInvalidValues(card).Should().Not.Be.Empty();

   card.number = "541234567890125"; //right CC (luhn compliant)
   classValidator.GetInvalidValues(card).Should().Be.Empty();

   card.ean = "9782266156066"; //right EAN
   classValidator.GetInvalidValues(card).Should().Be.Empty();

   card.ean = "9782266156067"; //wrong EAN
   classValidator.GetInvalidValues(card).Should().Not.Be.Empty();
}

Now, using SharpTestsEx, we can run the same test with xUnit, MsTests, MbUnit (if/when we will need/want change the unit test framework) and I can’t see where it is more verbose.

Refactoring step 3

[Test]
public void GivingValidState_NoInvalidValues()
{
   var card = new CreditCard {Number = "541234567890125", Ean = "9782266156066"};
   var classValidator = GetClassValidator(typeof(CreditCard));

   classValidator.GetInvalidValues(card).Should().Be.Empty();
}

[Test]
public void GivingInvalidState_HasInvalidValues()
{
   var card = new CreditCard {Number = "1234567890123456", Ean = "9782266156067"};
   var classValidator = GetClassValidator(typeof(CreditCard));

   classValidator.GetInvalidValues(card).Should().Have.Count.EqualTo(2);
}

Perhaps SharpTestsEx is a little bit more verbose, in some cases, but with your help we can improve it.