void () { List<Integer> childLog = new ArrayList<>(); service().runTaskSynchronously(new DumbModeTask() { @Override public void performInDumbMode(@NotNull ProgressIndicator indicator) { for (int i = 0; i < 100; i++) { int taskId = i; service().runTaskSynchronously(new DumbModeTask() { @Override public void performInDumbMode(@NotNull ProgressIndicator indicator) { childLog.add(taskId); } }); } } }); Assert.assertEquals("Every child task are not unique, all must be executed: " + childLog, 100, childLog.size()); }