How to test file upload in Laravel 5.2

When you create an instance of UploadedFile set the last parameter $test to true.

$file = new UploadedFile($path, $name, filesize($path), 'image/png', null, true);
                                                                           ^^^^

Here is a quick example of a working test. It expects that you have a stub test.png file in tests/stubs folder.

class UploadTest extends TestCase
{
    public function test_upload_works()
    {
        $stub = __DIR__.'/stubs/test.png';
        $name = str_random(8).'.png';
        $path = sys_get_temp_dir().'/'.$name;

        copy($stub, $path);

        $file = new UploadedFile($path, $name, filesize($path), 'image/png', null, true);
        $response = $this->call('POST', '/upload', [], [], ['photo' => $file], ['Accept' => 'application/json']);

        $this->assertResponseOk();
        $content = json_decode($response->getContent());
        $this->assertObjectHasAttribute('name', $content);

        $uploaded = 'uploads'.DIRECTORY_SEPARATOR.$content->name;
        $this->assertFileExists(public_path($uploaded));

        @unlink($uploaded);
    }
}

➔ phpunit tests/UploadTest.php
PHPUnit 4.8.24 by Sebastian Bergmann and contributors.

.

Time: 2.97 seconds, Memory: 14.00Mb

OK (1 test, 3 assertions)

In Laravel 5.4 you can also use \Illuminate\Http\UploadedFile::fake(). A simple example below:

/**
 * @test
 */
public function it_should_allow_to_upload_an_image_attachment()
{
    $this->post(
        action('AttachmentController@store'),
        ['file' => UploadedFile::fake()->image('file.png', 600, 600)]
    );

    /** @var \App\Attachment $attachment */
    $this->assertNotNull($attachment = Attachment::query()->first());
    $this->assertFileExists($attachment->path());
    @unlink($attachment->path());
}

If you want to fake a different file type you can use

UploadedFile::fake()->create($name, $kilobytes = 0)

More information directly on Laravel Documentation.