The first step in unit testing is to isolate the piece of code to be tested. This is done by placing it into a class or function library. Testing data is important for the effectiveness of this isolation because it allows developers to verify that their code works properly in a variety of scenarios. One way to do this would be by manually entering them as arguments every time you want to run one of your test cases - which can get tedious very quickly! A faster option would be using Test Data Libraries (TDLs).
Let’s see the 11 best open-source C# Testing Data Libraries in 2022: GenFu - generate realistic test data; AutoFixture - open source library for .NET designed; Bogus - sane fake data generator.