Cleaning up after adding files in Drupal Behat tests

I've been going kind of crazy covering a particular Drupal site I'm building in Behat tests—testing every bit of core functionality on the site. In this particular case, a feature I'm testing allows users to upload arbitrary files to an SFTP server, then Drupal shows those filenames in a streamlined UI.

I needed to be able to test the user action of "I'm a user, I upload a file to this directory, then I see the file listed in a certain place on the site."

These files are not managed by Drupal (e.g. they're not file field uploads), but if they were, I'd invest some time in resolving this issue in the drupalextension project: "When I attach the file" and Drupal temporary files.

Since they are just random files dropped on the filesystem, I needed to:

1. Create a new step definition
2. Track files that are created using that step definition
3. Add code to make sure files that were created are cleaned up

If I just added a new step definition in my FeatureContext which creates the new files, then subsequent test runs on the same machine would likely fail, because the test files I created are still present.

Luckily, Behat has a mechanism that allows me to track created resources and clean up after the scenario runs (even if it fails), and those in Drupal-land may be familiar with the naming convention—they're called hooks.

In this case, I want to add an @AfterScenario hook which runs after any scenario that creates a file, but I'm getting a little ahead of myself here.

Create a new step definition

Whenever I want to create a new step definition, I start by writing out the step as I want it, in my feature file:

When I add file "test.txt" to the "example" folder

Now I run the scenario using Behat, and Behat is nice enough to generate the stub function I need to add to my FeatureContext in it's output:

I copy that code out, drop it into my FeatureContext, then change things to do what I want:

  /**
   * @When I add file :file_name to the :folder_name folder
   */
  public function iAddFileToTheFolder($file_name, $folder_name) {
    $file_path = '/some/system/directory/' . $folder_name . '/' . $file_name;
    $file = fopen($file_path, 'w');
    fwrite($file, '');
    fclose($file);
  }

Yay, a working Behat test step! If I run it, it passes, and the file is dropped into that folder.

But if I run it again, the file was already there and the rest of my tests may also be affected by this rogue testing file.

So next step is I need to track the files I create, and make sure they are cleaned up in an @AfterScenario.

Track files created during test steps

At the top of my FeatureContext, I added:

  /**
   * Keep track of files added by tests so they can be cleaned up.
   *
   * @var array
   */
  public $files = [];

This array tracks a list of file paths, quite simply.

And then inside my test step, at the end of the function, I can add any file that is created to that array:

  /**
   * @When I add file :file_name to the :folder_name folder
   */
  public function iAddFileToTheFolder($file_name, $folder_name) {
    $file_path = '/some/system/directory/' . $folder_name . '/' . $file_name;
    $file = fopen($file_path, 'w');
    fwrite($file, '');
    fclose($file);
    $this->files[] = $file_path;
  }

That's great, but next we need to add an @AfterScenario hook to clean up the files.

Make sure the created files are cleaned up

At the end of my feature context, I'll add a cleanUpFiles() function:

This @AfterScenario is tagged with @file, so any scenario where I want the files to be tracked and cleaned up, I just need to add the @file tag, like so:

And that is how you do it. Now no matter whether I create one file or a thousand, any scenario tagged with @file will get all its generated test files cleaned up afterwards!