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Announcing the TDD TestHelpers opensource project

Whenever I start working on a project; I invariably find myself writing a collection of TDD test helper methods.  I quick survey of other TDDers reveals the same; and thus the birth of my latest opensource project, TestHelpers (http://code.google.com/p/testhelpers/).

The aim of the project is to centralise all those little test helper methods you end up creating into a useful assembly you can use to jumpstart your next project.  Things like:

  • Comparers
    • Generic object comparers
    • DataSet comparers
  • Test Data generators
    • Builder pattern
  • Automocking containers

For example, I’ve just added an “AssertValues” functor; which helps you check whether the values of who object instances are the same. 

One area I keep using asserts like this is in integration tests; where I want to check that the objects I’m persisting to the database via my ORM actually end up in the database in a non-mangled form.  In this case, I new up entityA, persist it, reload it into entityB and then need to check that all the values in entityB are the same as those in entityA.

A standard Assert.AreEqual will fail, because entityA and entityB are different instances.  But, my helper method AssertValues.AreEqual will pass, because it checks the (serialized) string values of entityA and entityB.

Here is another, simpler example to illustrate the concept.

    [TestFixture]
    public class StandardObjectsTests
    {
        public class StringContainer
        {
            public string String1 { get; set; }
            public string String2 { get; set; }
        }

        [Test]
        public void ObjectsWithSameValue_ShouldBeEqual()
        {
            var stringContainer1 = new StringContainer {String1 = "Test String1", String2 = "Test String 2"};
            var stringContainer2 = new StringContainer {String1 = "Test String1", String2 = "Test String 2"};

            Assert.AreNotEqual(stringContainer1, stringContainer2);

            AssertValues.AreEqual(stringContainer1, stringContainer2);
        }
   }

I’m sure you have a bunch of similar helper methods lying about your projects.

How about contributing them to the TestHelper project?


So, what do you think ?