3.9. State

You can also find this code on GitHub

State.php

<?php
 
namespace DesignPatterns\Behavioral\State;
 
interface State
{
    public function proceedToNext(OrderContext $context);
 
    public function toString(): string;
}

StateCreated.php

<?php
 
namespace DesignPatterns\Behavioral\State;
 
class StateShipped implements State
{
    public function proceedToNext(OrderContext $context)
    {
        $context->setState(new StateDone());
 
    public function toString(): string
    {
        return 'shipped';
    }
}

StateDone.php

Tests/StateTest.php

<?php
 
namespace DesignPatterns\Behavioral\State\Tests;
 
use DesignPatterns\Behavioral\State\OrderContext;
use PHPUnit\Framework\TestCase;
 
class StateTest extends TestCase
{
    public function testIsCreatedWithStateCreated()
    {
        $orderContext = OrderContext::create();
 
        $this->assertEquals('created', $orderContext->toString());
    }
 
    public function testCanProceedToStateShipped()
        $contextOrder = OrderContext::create();
        $contextOrder->proceedToNext();
 
        $this->assertEquals('shipped', $contextOrder->toString());
    }
 
    public function testCanProceedToStateDone()
    {
        $contextOrder = OrderContext::create();
        $contextOrder->proceedToNext();
        $contextOrder->proceedToNext();
 
        $this->assertEquals('done', $contextOrder->toString());
    }
 
    public function testStateDoneIsTheLastPossibleState()
    {
        $contextOrder = OrderContext::create();
        $contextOrder->proceedToNext();
        $contextOrder->proceedToNext();
        $contextOrder->proceedToNext();
 
        $this->assertEquals('done', $contextOrder->toString());
}