Webmozart\Console\Api\Config\CommandConfig::addAlias PHP Method

    public function addAlias($alias)
    {
        Assert::string($alias, 'The command alias must be a string. Got: %s');
        Assert::notEmpty($alias, 'The command alias must not be empty.');
        Assert::regex($alias, '~^[a-zA-Z0-9\\-]+$~', 'The command alias should contain letters, digits and hyphens only. Got: %s');
        $this->aliases[] = $alias;
        return $this;
    }

 public function testSetAliases()
 {
     $this->config->addAlias('alias1');
     $this->config->setAliases(array('alias2', 'alias3'));
     $this->assertSame(array('alias2', 'alias3'), $this->config->getAliases());
 }