I use AutoFixture for generating test data in my unit tests. AutoFixture has served me well, but the documentation doesn’t give great examples of how to use it. The “cheat sheet” has links to the authors blogs, and if you’re not careful you won’t find everything you need. It’s sometimes easy to miss those links.

The other day, I was trying to generate a POCO that had a string property, and I wanted that string property to be constrained to a list of valid values. Since I obviously didn’t want to customize the string type across my entire fixture, I instead customized the parent type with the Do method. I wanted to pass in an action that would randomly select from the list pre-defined values and then assign it to the string property in my class instance. The code was straight-forward, but the string was still being populated with the default AutoFixture value.

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