Java Projects - Second Edition

Unit tests are deterministic

Our unit test is deterministic. Non-deterministic unit tests are the nightmare of developers. If you are in a group where some builds break on the CI server, and when a build breaks, your fellow developer says that you just have to try it again; no way! If a unit test runs, it should run at all times. If it fails, it should fail no matter how many times you start it. A non-deterministic unit test, in our case, would be to render random numbers and have them sorted. It would end up with different arrays in each test run and, in case there is some bug in the code that manifests for some array, we will not be able to reproduce it. Not to mention that the assertion to ensure the code was running fine is also difficult ...