Laravel Tutorial - Testing

Laravel - Laravel makes HTTP testing a breeze for performing integration tests against routes and middleware, so let’s write a few feature tests to verify our code works as expected.

Before we get started, we need to adjust a few things in our phpunit.xml file so that we can use an in-memory SQLite database. You will need to make sure that you have the proper PHP modules installed.

Using environment variables, we can change the database connection by adding a few new variables to the config:

<php>
        <!-- ... -->
    <env name="DB_CONNECTION" value="sqlite"/>
    <env name="DB_DATABASE" value=":memory:"/>
        <!-- ... -->
</php>
Next, remove the placeholder test that ships with Laravel:

rm tests/Feature/ExampleTest.php
We are ready to start testing the /submit form through HTTP requests to make sure that the route validation, saving, and redirecting are working as expected.

First, let’s create a new feature test to test against our route:

php artisan make:test SubmitLinksTest
The command creates a new testing file with the proper dependencies, including a RefreshDatabase trait that we are going to use to verify that our links are being saved to the database when valid.

Open the new tests/Feature/SubmitLinksTest.php file and let’s define a few skeleton tests in the body of the class that we are going to flesh out:

/** @test */
function guest_can_submit_a_new_link() {}

/** @test */
function link_is_not_created_if_validation_fails() {}

/** @test */
function link_is_not_created_with_an_invalid_url() {}

/** @test */
function max_length_fails_when_too_long() {}

/** @test */
function max_length_succeeds_when_under_max() {}
These tests should give you a high-level overview of what we are going to test:

Verify that valid links get saved in the database
When validation fails, links are not in the database
Invalid URLs are not allowed
Validation should fail when the fields are longer than the max:255 validation rule
Validation should succeed when the fields are long enough according to max:255.
We might be missing some things, but for your first Laravel application, this is a decent list that should illustrate some basic HTTP testing techniques in Laravel.

Saving a valid link
The first test we’ll write is the test that verifies that valid data gets stored in the database:

<?php

namespace Tests\Feature;

use Illuminate\Validation\ValidationException;
use Tests\TestCase;
use Illuminate\Foundation\Testing\RefreshDatabase;

class SubmitLinksTest extends TestCase
{
    use RefreshDatabase;

    /** @test */
    function guest_can_submit_a_new_link()
    {
        $response = $this->post('/submit', [
            'title' => 'Example Title',
            'url' => 'http://example.com',
            'description' => 'Example description.',
        ]);

        $this->assertDatabaseHas('links', [
            'title' => 'Example Title'
        ]);

        $response
            ->assertStatus(302)
            ->assertHeader('Location', url('/'));

        $this
            ->get('/')
            ->assertSee('Example Title');
    }
}
Take note of the RefreshDatabase trait which makes sure that each test has a new database to give each test a pristine database environment with all the migrations.

Our first test submits valid post data, which returns a response object that we can use to assert that our route responded as expected. We verify that the database contains a record with the title we just created.

Next, we verify that the response was a 302 status code with a Location header pointing to the homepage.

Last, we request the home page and verify that the link title is visible on the homepage.

Testing Failed Validation
When a user generally submits bad data, we expect the validation to trigger an exception and we can use that to make sure our validation layer is working:

/** @test */
function link_is_not_created_if_validation_fails()
{
    $response = $this->post('/submit');

    $response->assertSessionHasErrors(['title', 'url', 'description']);
}
We use Laravel’s assertSessionHasErrors() to make sure that the session has validation errors for each of our required fields. Because we submitted empty data to the route, we expect the required rule will trigger for each field.

Let’s run the test suite to verify our work thus far:

$ vendor/bin/phpunit
PHPUnit 6.4.3 by Sebastian Bergmann and contributors.

...                                                                 3 / 3 (100%)

Time: 173 ms, Memory: 16.00MB

OK (3 tests, 10 assertions)
Testing URL Validation
We expect only valid URLs to pass validation so that our application doesn’t try to display invalid data.

/** @test */
function link_is_not_created_with_an_invalid_url()
{
    $this->withoutExceptionHandling();

    $cases = ['//invalid-url.com', '/invalid-url', 'foo.com'];

    foreach ($cases as $case) {
        try {
            $response = $this->post('/submit', [
                'title' => 'Example Title',
                'url' => $case,
                'description' => 'Example description',
            ]);
        } catch (ValidationException $e) {
            $this->assertEquals(
                'The url format is invalid.',
                $e->validator->errors()->first('url')
            );
            continue;
        }

        $this->fail("The URL $case passed validation when it should have failed.");
    }
}
Laravel 5.5 introduced the withoutExceptionHandling() method which disables Laravel’s route exception handling code used to generate an HTTP response after an exception. We use this to our advantage so we can inspect the validation exception object and assert against the error messages.

We loop through various cases (add your own if you’d like to cover more scenarios) and catch instances of ValidationException. If the text makes it past the exception handling, we manually fail the test because we expect the route throws a ValidationExcepiton exception each time.

The catch block uses the validator object to check the url error and asserts that the actual error message matches the expected validation error message.

I like using the try/catch technique, followed by a $this->fail() as a safety harness instead of using exception annotations provided by PHPUnit. I feel catching the exception allows the ability to do assertions that wouldn’t otherwise be possible and provides a more granular control that I like in most cases.

Testing Max Length Validation
We will test a few scenarios with the max:255 validations rules: when the field fails max-length validation with a length of 256 characters, and when the field is long enough to pass validation at 255 characters.

Although Laravel contains the max validation rule functionality, I like to test it to verify that my application applies the rules. If someone removes the max validation rule, then the tests will catch it.

I like to test the threshold of min and max validation rules as an extra caution to make sure my application respects the min and max boundaries I set.

First, let’s test the “max length” scenario:

/** @test */
function max_length_fails_when_too_long()
{
    $this->withoutExceptionHandling();

    $title = str_repeat('a', 256);
    $description = str_repeat('a', 256);
    $url = 'http://';
    $url .= str_repeat('a', 256 - strlen($url));

    try {
        $this->post('/submit', compact('title', 'url', 'description'));
    } catch(ValidationException $e) {
        $this->assertEquals(
            'The title may not be greater than 255 characters.',
            $e->validator->errors()->first('title')
        );

        $this->assertEquals(
            'The url may not be greater than 255 characters.',
            $e->validator->errors()->first('url')
        );

        $this->assertEquals(
            'The description may not be greater than 255 characters.',
            $e->validator->errors()->first('description')
        );

        return;
    }

    $this->fail('Max length should trigger a ValidationException');
}
Again, we disable exception handling and create data that is one character too long to pass validation.

We assert each field to make sure they all have a max length validation error message.

Last, we need to return in the caught exception and use the $this->fail() as a safety harness to fail the test.

Next, we test the “under the max” scenario:

/** @test */
function max_length_succeeds_when_under_max()
{
    $url = 'http://';
    $url .= str_repeat('a', 255 - strlen($url));

    $data = [
        'title' => str_repeat('a', 255),
        'url' => $url,
        'description' => str_repeat('a', 255),
    ];

    $this->post('/submit', $data);

    $this->assertDatabaseHas('links', $data);
}
We make the form data long enough to pass max:255 validation and assert that the data is in the database after submitting the data.

Run the test suite and make sure everything is passing:

$ vendor/bin/phpunit
PHPUnit 6.4.3 by Sebastian Bergmann and contributors.

......                                                              6 / 6 (100%)

Time: 197 ms, Memory: 16.00MB

OK (6 tests, 17 assertio