Laravel test helper for creating a temporary file upload with contents.

UploadedFileTestHelper.php

<?php

namespace Tests\Helpers;

class UploadedFileTestHelper
{
    /**
     * Create a fake file upload with the contents
     *
     * @param mixed $contents  The contents of the temporary file
     * @return UploadedFile
     */
    public function makeRequestFile($contents, $kilobytes = 2)
    {
        $tempFile = tmpfile();
        fwrite($tempFile, $json);
        fseek($tempFile, 0);

        return UploadedFile::createFromBase(
            tap(new \Illuminate\Http\Testing\File('request,json', $tempFile), function ($file) uses ($kilobytes) {
                $file->sizeToReport = $kilobytes * 1024;
            })
        );
    }
}