Today I used two features in NUnit that I have never used before and I thought I would share for those who have yet to discover these great features as well.
TestFixture Parameters
Did you know that the TestFixtureAttribute can take parameters?
1: [TestFixture("My Name")]Did you know that you can place more than one on your class?
1: [TestFixture("My Name")] 2: [TestFixture("Your Name")] 3: public class SimpleTests
4: { 5: }
I have recently been writing normal NUnit tests in a BDD influenced style. I know there are frameworks like SpecFlow and machine.specifications that are better then what I am doing, but at work I am trying to reduce the number of frameworks I introduce in a week, and those two are pretty invasive in that they both require VS2102 integrations for their maximum benefit.
For my BDD-ish test I have taken to making test fixtures that look like this
1: [TestFixture]
2: public class SimpleGreeterTests
3: { 4: [SetUp]
5: public void SetUp()
6: { 7: EstablishContext();
8: given_I_have_a_name();
9: when_the_greeter_greets();
10: }
11:
12: [Test]
13: public void then_the_greeting_should_say_hello()
14: { 15: Assert.That(Result, Is.EqualTo(string.Format("Hello {0}", Name))); 16: }
17:
18: protected string Name { get; set; } 19: protected IGreeter Subject { get; set; } 20: protected string Result { get; set; } 21:
22: protected void EstablishContext()
23: { 24: Subject = new Greeter();
25: }
26:
27: protected void given_I_have_a_name()
28: { 29: Name = RandomDataHelper.Get<string>();
30: }
31:
32: protected void when_the_greeter_greets()
33: { 34: Result = Subject.Greet(Name);
35: }
36: }
This pattern is something I am really enjoying and not the real topic here.
Today I created a test very similar in nature to this. I my case I need to code to return something different based on specific values of name. I thought I would have to write multiple suites. I knew I could execute a test multiple times with the TestCase attribute, but with this BDD structure to my tests, I needed the data to vary within the scope of the SetUp method.
Luckily NUnit introduced TestFixture parameters in 2.5. Which allowed me to make a test like this
1: [TestFixture("Jimmy", "Hello Mr. Bosse")] 2: [TestFixture("Lisa", "Hello Mrs. Bosse")] 3: public class SimpleGreeterTests
4: { 5: [SetUp]
6: public void SetUp()
7: { 8: EstablishContext();
9: given_my_name_is(_name);
10: when_the_greeter_greets();
11: }
12:
13: [Test]
14: public void then_the_greeting_should_say_hello()
15: { 16: Assert.That(Result, Is.EqualTo(_greeting));
17: }
18:
19: protected string Name { get; set; } 20: protected IGreeter Subject { get; set; } 21: protected string Result { get; set; } 22:
23: public SimpleGreeterTests(string name, string greeting)
24: { 25: _name = name;
26: _greeting = greeting;
27: }
28:
29: protected void EstablishContext()
30: { 31: Subject = new Greeter();
32: }
33:
34: protected void given_I_have_a_name(string name)
35: { 36: Name = name;
37: }
38:
39: protected void when_the_greeter_greets()
40: { 41: Result = Subject.Greet(Name);
42: }
43: }
CollectionAssert.Order
The next little gem I discovered was the more robust asserts NUnit lets you do against collections. For years I have been testing that my arrays contain the same elements
Assert.That(thisArray, Is.EquivalentTo(thatArray));
but today I needed to make sure my array was in the correct order. Through the magic of intellisense I was able to find this little nugget
Assert.That(thisArray, Is.Ordered.By("LastName"));Lesson Learned
While my approach to new frameworks is often to find out just enough to get me going on the thing I am building right now, I think I will try harder to fight TL;DR; and spend more time in the nooks and crannies.
