### Question:
SystemBean implements CommandListener { @Command public String env() { final PrintString out = new PrintString(); final Map<String, String> env = System.getenv(); for (String key : new TreeSet<String>(env.keySet())) { out.printf("%s = %s%n", key, env.get(key)); } return out.toString(); }  @Command String date(); @Command String env(); @Command String properties();  }### Answer:
@Test public void testEnv() throws Exception { final String env = (String) main.exec("env"); assertNotNull(env); final Set<String> systemEnvKeys = System.getenv().keySet(); for (String key : systemEnvKeys) { assertTrue(env.contains(key)); } }