NUnit_guidelines.md

NUnit Guide

These are some guidelines on how to better use the NUnit framework. We provide some code examples, as well as make some arguments about how to create well-structured tests.

Providing arguments

You can provide arguments to a test method by using the [TestCase] attribute.

using NUnit.Framework;

namespace Tests
{
    [TestFixture]
    public class Test
    {
        [TestCase(12, 45, 13)]
        [TestCase(24, 90, 26)]
        [TestCase(48, 180, 52)]
        public void ParameterizedSameTest (int a, int b, int c)
        {
            Assert.AreEqual (SomeMethod (a, b), c);
        }
        // This test is run 3 times
    }
}

Setup

NUnit provides the SetUp attribute that can be attached to any method within an NUnit test class. This method will then be called automatically prior to any other test method that you have defined within the same class.

using NUnit.Framework;

namespace Tests
{
    [TestFixture]
    public class Test
    {
        private int counter;
        
        [SetUp ()]
        public void Init ()
        {
            this.counter = 0;
        }
        
        [Test(), Repeat(100)]
        public void TestCounter ()
        {
            counter++;
            Assert.AreEqual (counter, 1);
        }
        // this test will be run 100 times
    }
}

Constraint-based assertion model

The idea is to provide constraints to the assertion function. Use Assert.That to provide an assertion model that expects a constraint, then use Is.<...> to provide the constraint.

using NUnit.Framework;

namespace Tests
{
    [TestFixture]
    public class Test
    {
        [Test]
        public void ConstraintNullTest ()
        {
            var x = SomeObjectCreatorMethod ();
            Assert.That (x, Is.Not.Null);
        }
        
        [Test]
        public void ConstraintNegativeTest ()
        {
            var x = Factorial (-23);
            Assert.That (x, Is.Positive);
        }
    }
}