Avoid Fakers in Unit Tests Unless you are fuzz testing or your goal is to create property-based tests, test data generators (a.k.a. fakers) are likely to do more harm than good in the long run.
What is a Unit Test? There is a lot of confusion about what unit tests are and how they differ from integration tests. This post provides one viewpoint on what unit tests are.
Duplication over Abstraction in Unit Tests In your production code, favor abstraction over duplication. In your unit tests, favor duplication over abstraction.
Are your Tests Necessary and Useful? Some automated tests are unnecessary or problematic. Here are some questions to ask yourself about each test you write.