The below is an excerpt from the latest chapter “An Introduction to Unit Testing With xUnit.net” from my book Keeping Software Soft.

xUnit.net provides a number of ways for checking (asserting) results are as expected.

The following explanatory tests shown the different types of assertions that xUnit.net supports:

using System;
using System.Collections.Generic;
using Xunit;

namespace KeepingSoftwareSoftSamples.XUnitTestingDemo
{
    public class XUnitAssertExamples
    {
        [Fact]
        public void SimpleAssertsThatOneValueEqualsAnother()
        {
            Assert.Equal(1, 2); // fail
            Assert.Equal("hello", "hello"); // pass

            Assert.NotEqual(1, 2); // pass
            Assert.NotEqual("hello", "hello"); // fail
        }

        [Fact]
        public void BooleanAsserts()
        {
            Assert.True(true); // pass
            Assert.True(false); // fail

            Assert.False(false); // pass
            Assert.False(true); // fail

            // Don't do this
            Assert.True(1 == 1); // pass
        }

        [Fact]
        public void Ranges()
        {
            const int value = 22;

            Assert.InRange(value, 21, 100); // pass
            Assert.InRange(value, 22, 100); // pass

            Assert.NotInRange(value, 999, 99999); // pass

            Assert.InRange(value, 23, 100); // fail
        }

        [Fact]
        public void Nulls()
        {
            Assert.Null(null); // pass

            Assert.NotNull("hello"); // pass

            Assert.NotNull(null); // fail
        }

        [Fact]
        public void ReferenceEquality()
        {
            var objectA = new Object();
            var objectB = new Object();

            Assert.Same(objectA, objectB); // fail

            Assert.NotSame(objectA, objectB); // pass
        }

        [Fact]
        public void AnIEnumberableContainsASpecificItem()
        {
            var days = new List<string>
                                 {
                                     "Monday",
                                     "Tuesday"
                                 };

            Assert.Contains("Monday", days); // pass
            Assert.Contains("Friday", days); // fail

            Assert.DoesNotContain("Friday", days); // pass
        }

        [Fact]
        public void IEnumerableEmptiness()
        {
            var aCollection = new List<string>();

            Assert.Empty(aCollection); // pass

            aCollection.Add("now no longer empty");

            Assert.NotEmpty(aCollection); // pass

            Assert.Empty(aCollection); // fail            
        }

        [Fact]
        public void IsASpecificType()
        {
            Assert.IsType<string>("hello"); // pass

            Assert.IsNotType<int>("hello"); // pass

            Assert.IsType<int>("hello"); // fail
        }

        [Fact]
        public void IsAssignableFrom()
        {
            const string stringVariable = "42";

            Assert.IsAssignableFrom<string>(stringVariable); // pass

            Assert.IsAssignableFrom<int>(stringVariable); // fail
        }
    }
}

To learn more about xUnit.net check out my xUnit.net Pluralsight course.

You can start watching with a Pluralsight free trial.

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