public Class<?> getCommandClass(String commandName) {
        if (hasCommand(commandName)) {
            return frameworkModel
                    .getExtensionLoader(BaseCommand.class)
                    .getExtension(commandName)
                    .getClass();
        } else {
            return null;
        }
    }
@Test
    void testGetCommandClass() {
        assertThat(commandHelper.getCommandClass("greeting"), equalTo(GreetingCommand.class));
        assertNull(commandHelper.getCommandClass("not-exiting"));
    }