Does anyone else have the same problems? On my system java-testng sometimes fails nondeterministically within the check phase: =============================================== TestNG Total tests run: 1633, Failures: 2, Skips: 0 =============================================== Failures in :TestNG, :Regression2 test.thread.ParallelTestTest.verifyParallel() StackTrace: java.lang.AssertionError: Expected size:<4> but was:<3> in: <{59L=59L, 60L=60L, 62L=62L}> at test.thread.ParallelTestTest.verifyExpected(Unknown Source) at test.thread.ParallelTestTest.verifyParallel(Unknown Source) ... Removed 24 stack frames test.thread.ParallelTestTest.verifyParallel() StackTrace: java.lang.AssertionError: Expected size:<4> but was:<3> in: <{55L=55L, 56L=56L, 58L=58L}> at test.thread.ParallelTestTest.verifyExpected(Unknown Source) at test.thread.ParallelTestTest.verifyParallel(Unknown Source) ... Removed 24 stack frames Do others experience this too, or is it just my machine? On berlin, everything looks fine, that makes we wonder: https://ci.guix.gnu.org/search?query=%5Ejava-testng We had some problems in the past with other parallel tests: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=30526 I also tried to update java-testng but that was not possible quickly, because of new/updated dependency-graph. Björn