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Testing CSV output in Drupal 8 with BrowserTestBase

In a recent project we were outputting CSV and wanted to test that the file contents were valid.

Read on for a quick tip on how to achieve this with Drupal 8's BrowserTestBase

by lee.rowlands /

Basically, the easiest way to validate and parse CSV in PHP is with the built in fgetcsv function.

So how do you go about using that inside a functional test - in that instance we're not dealing with a file so its not your ordinary approach for fgetcsv.

The answer is to create a stream wrapper in memory, and use fgetcsv on that.

The code looks something like this:

    $response = $this->getSession()
    // Put contents into a memory stream and use fgetcsv to parse.
    $stream = fopen('php://memory', 'r+');
    fwrite($stream, $response);
    $records = [];
    // Get the header row.
    $header = fgetcsv($stream);
    while ($row = fgetcsv($stream)) {
      $records[] = $row;

There you have it, you now have the header in $header and the rows in $rows and can do any manner of asserts that you need to validate the CSV generation works as expected.

Posted by lee.rowlands
Senior Developer