Unit testing

Fixing bugs in code is expensive. The earlier that a bug is discovered in the development process, the less expensive it will be to fix.

Unit testing is a good 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, and this is called Test-Driven Development (TDD).

Microsoft has a proprietary unit testing framework known as MS Test. There is also a framework named NUnit. However, we will use the free and open-source third-party framework xUnit.net. xUnit was created by the same team that built NUnit but they fixed the mistakes they felt they made previously. xUnit is more extensible and has better community support.

Understanding types of testing

Unit testing is just one of many types of testing, as described in the following table:

Type of testing

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