Creating a file in a named constructor

Question

I have a class that creates a file via a named constructor but when I test it using phpspec it does not create the file.

I can't find the reason for that, so I guess a fresh look at my code could help.

Here's my File class:

<?php

namespace Acme;

class File
{
    /**
     * @var Path
     */
    private $path;

    /**
     * @var FileName
     */
    private $fileName;

    private function __construct(Path $path, FileName $fileName)
    {
        $this->path = $path;
        $this->fileName = $fileName;
    }

    public static function create(Path $path, FileName $fileName)
    {
        if (file_exists((string) $path . (string) $fileName)) {
            throw new \DomainException('File already exists');
        }

        if (!touch((string) $path . (string) $fileName)) {
            throw new \DomainException('Cannot create file');
        }

        return new self($path, $fileName);
    }
}

Here my spec:

<?php

namespace spec\Acme;

use PhpSpec\ObjectBehavior;
use Prophecy\Argument;
use Acme\Path;
use Acme\FileName;

class FileSpec extends ObjectBehavior
{

    private $testPath;
    private $existingFileName = 'existingFile.extension';
    private $nonExistingFileName = 'nonExistingFile.extension';
    private $existingFilePath;
    private $nonExistingFilePath;

    function let()
    {
        $this->testPath = sys_get_temp_dir() . '/';
        $this->existingFilePath = $this->testPath . $this->existingFileName;
        $this->nonExistingFilePath = $this->testPath . $this->nonExistingFileName;

        // Creating existing file
        if (!touch($this->existingFilePath)) {
            throw new \Exception('Cannot create existing file for testing');
        }

        // Removes non existing file
        if (file_exists($this->nonExistingFilePath)) {
            if (!unlink($this->nonExistingFilePath)) {
                throw new \Exception('Cannot remove non existing file for testing');
            }
        }
    }

    function it_does_not_create_a_file_when_the_file_already_exists(Path $path, FileName $fileName)
    {
        $path->__toString()->willReturn($this->testPath);
        $fileName->__toString()->willReturn($this->existingFileName);
        $this->beConstructedThrough('create', [$path, $fileName]);
        $this->shouldThrow(new \DomainException('File already exists'))->duringInstantiation();
    }

    function it_creates_a_new_file_if_file_does_not_exist(Path $path, FileName $fileName)
    {
        $path->__toString()->willReturn($this->testPath);
        $fileName->__toString()->willReturn($this->nonExistingFileName);
        $this->beConstructedThrough('create', [$path, $fileName]);
        assert(file_exists($this->nonExistingFilePath));
    }
}

Answer 1

This is because phpspec will not instantiate the class until required to do so. Only method calls or expectations (i.e. should*) against the original class itself will result in in it being instantiated, and beConstructedThrough is simply a hint as to how it phpspec should gain an instance.

Now, you could work around this by calling into some method, or perhaps even just calling $this->shouldHaveType(File::class), but I'd suggest rethinking the approach. If you're ultimately integrating into something external -- be it an SDK, filesystem, database, etc, you'll be much better off writing an integration test. Which you're pretty close to doing in this case anyway (mocking shouldn't really be necessary). phpspec is more aimed towards specifying the behaviour/logic of classes and methods.. describing side effects does not really fit within it's remit. Usage of assert() here is a hint towards that too, as this is certainly not idiomatic for phpspec backed specifications.

For an integration test, PHPUnit would be a better choice, as it's more general purpose.. so you'll have the flexibility to instantiate and assert as required.