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15 November 2009

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.

2 comments:

  1. I've been using SharpTextsEx and I have to admit that at first I was feeling like writing a lot of unnecessarily code. But now when I have to see (and work with) tests that don't use the extensions I have to spend more time trying to understand each assert. That is why now I write all my tests using SharpTextxEx.

    Thanks, and keep up the good work.

    ReplyDelete
  2. That is the reason because I'm using #TestsEx in NHV.

    ReplyDelete