Mocking the Filesystem during BDD with Behat and PHPSpec - www.slashnode.com

FeatureContext.php

<?php

/** ... etc ... */

class FeatureContext implements SnippetAcceptingContext
{
    protected $filesystem;
    protected $config;
    protected $sut;

    /**
     * Initializes context.
     */
    public function __construct()
    {
        $this->config = [];
    }

    /**
     * @Given there is a configuration file
     */
    public function thereIsAConfigurationFile()
    {
        // synchronises the "file system" with the contents of $this->config
        $this->updateConfig();
    }

    /**
     * @Given the option :arg1 is configured to :arg2
     */
    public function theOptionIsConfiguredTo($arg1, $arg2)
    {
        $this->config[$arg1] = $arg2;
        $this->updateConfig();
    }

    /**
     * @When I load the configuration file
     */
    public function iLoadTheConfigurationFile()
    {
        $this->sut = Config::load(vfsStream::url('home/config.php'));
    }

    /** ...etc... */

    private function updateConfig()
    {
        // build the file contents
        $config = '<?php return ' . var_export($this->config, true) . ';';

        // update the file system with the new config "file"
        $this->filesystem = vfsStream::setup('home', null, [
            'config.php' => $config
        ]);
    }
}