The test TestClassFinder#testClassFinderDefaultsToOwnPackage compares two sets from allClassesFinder.findClasses. However, the function allClassesFinder.findClasses does not return the deterministic order result. From code trace, the root cause is at ClassFinder.findClassesFromJar and ClassFinder.findClassesFromFiles. They use HashSet to store classes and listFiles to get file array. However, HashSet and listFiles do not guarantee that order, and the assertion can fail if the order differs.