Pragmatic Unit Testing in Java with JUnit, 3rd Edition

Avoiding Dependency Despair: Don’t Order Your Tests!

JUnit tests don’t run in their declared (top to bottom) order. In fact, they don’t run in any order that you’d easily be able to determine or depend on, such as alphabetically. (They’re likely returned in the order that a call to java.lang.Class.getMethods() returns, which is “not sorted and not in any particular order,” per its Javadoc.)

You might be tempted to think you want your tests to run in a specific order: “I’m writing a first test around newly created accounts, which have a zero balance. A second test can add $100 to the account, and I can verify that amount. I can then add a test that runs third, in which I’ll deposit $50 and ensure that the new balance is $150.”

While JUnit 5 provides ...