Fixing bugs in code is costly. The earlier a bug is discovered, the less expensive it will be to fix. Unit testing is a great way to find bugs early in the development process. Some developers even follow the principle that programmers should create unit tests before they write code. This is called Test Driven Development (TDD).
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You can learn more about unit testing at the following link:https://docs.microsoft.com/en-us/dotnet/core/testing/ You can learn more about TDD at the following link:https://en.wikipedia.org/wiki/Test-driven_development
Microsoft has a proprietary unit testing framework known as MS Test, which is closely integrated with Visual Studio. However, to use a unit testing framework that is compatible with .NET Core, we will use the third-party framework xUnit.net.