This is a simple application that does nothing except demonstrate some concepts about unit testing.

The main application, UnitTestDemo, is a .NET console application that demonstrates how write code using dependency injection in order to isolate the functionality of objects in a way that allows them to be put through automated testing tools.

The UnitTestDemo.nUnit project is a .NET class library that contains the automated tests. Each class that contains methods run by the testing tool injects stub, or mock, classes into the objects that require them. This allows the code inside those classes to be tested with known sets of data. The code in these classes being tested is also tested in isolation from the actual implementations that it depends on - in other words, you can test your business logic without depending on the database code to behave as expected. This allows easier debugging when something goes wrong.

The UnitTestDemo.nUnit project requires the NUnit NuGet package.

To run the nUnit tests, I recommend installing the NUnit Test Adapter in Visual Studio

To use the Test Adapter, you will want to open Test -> Windows -> Test Explorer. There will be no tests at first in the Test Explorer. Once you compile the projects, the tests should appear. You can just hit Run All to execute the tests.