try {
ByteArrayOutputStream printed = new ByteArrayOutputStream();
PrintStream spiedErr = spy(new PrintStream(printed));
System.setErr(spiedErr);
JumiBootstrap bootstrap = new JumiBootstrap();
bootstrap.suite.setTestClasses(OnePassingTest.class);
bootstrap.daemon.setIdleTimeout(0); // we want the daemon process to exit quickly
bootstrap.setTextUiOutput(new NullWriter());
bootstrap.enableDebugMode(); // <-- the thing we are testing
bootstrap.runSuite();
Thread.sleep(50); // wait for the daemon process to exit, and our printer thread to notice it
assertThat("this test has a problem; daemon printed nothing", printed.size(), is(not(0)));
verify(spiedErr, never()).close(); // <-- the thing we are testing