使用at（）功能的PHPUNIT模拟工作很奇怪

Question

here is the following code sample

<?php

interface iFS
{
    public function read();
    public function write($data);
}

class MyClass
{
    protected $_fs = null;

    public function __construct(iFS $fs)
    {
        $this->_fs = $fs;
    }

    public function run(array $list)
    {
        foreach ($list as $elm)
        {
            $this->_fs->write($elm);
        }

        return $this->_fs->read();
    }
}

class MyTests extends PHPUnit_Framework_TestCase
{
    public function testFS()
    {
        $mock = $this->getMock('iFS');
        $mock->expects($this->at(0))
                ->method('read')
                ->will($this->returnValue('tototatatiti'));

        $c = new MyClass($mock);
        $result = $c->run(array('toto', 'tata', 'titi'));

        $this->assertEquals('tototatatiti', $result);
    }
}

This is absolutely not a real case but it make happen something strange with phpunit and at($index) feature.

My question is pretty simple, is it normal that the test fails?

I explicitely asked to return "tototatatiti", but it never happens...

When

• I remove the line $this->_fs->write($elm); or
• I replace $mock->expects($this->at(0)) by $mock->expects($this->once())

The test pass to green

Is there something I don't understand?

EDIT:

$mock->expects($this->at(3)) ->method('read') ->will($this->returnValue('tototatatiti'));

=> Will make the test pass green...

Answer 1

I think the phpunit at() features is not usefull to stub different return result for a mocked method if the mocked object contains some other methods witch are calls too...

If you want to test something like:

$stub->expects($this->at(0))
                ->method('read')
                ->will($this->returnValue("toto"));

$stub->expects($this->at(1))
                ->method('read')
                ->will($this->returnValue("tata"));

You should better use something like

$stub->expects($this->exactly(2))
                ->method('read')
                ->will($this->onConsecutiveCalls("toto", "tata));