CompleteCommandTest_HelloCommand example

class CompleteCommandTest extends TestCase
{
    private CompleteCommand $command;
    private Application $application;
    private CommandTester $tester;

    protected function setUp(): void
    {
        $this->command = new CompleteCommand();

        $this->application = new Application();
        $this->application->add(new CompleteCommandTest_HelloCommand());

        $this->command->setApplication($this->application);
        $this->tester = new CommandTester($this->command);
    }

    public function testRequiredShellOption()
    {
        $this->expectExceptionMessage('The "--shell" option must be set.');
        $this->execute([]);
    }