TestClient.testBasics() test checks error messages for the case of usage non-existent commands. But it contains block for help command which exists in yarn and supported by Drill (see CommandLineOptions.Command enum).
This test shares the same TestContext instance for all the tests, but for some envs, TestContext.getOut() may return the result of the execution of previous block. So for some systems this test passes and for other may fail.
The solution is to add TestContext.resetOutput() calls for every test block and remove block with help command since it contradicts test javadoc.