Example of a unit test for an implementation of a Twitter Profile PHP class taken from a project at work, using PHPUnit

TwitterProfileTest.php

<?php
namespace App\Tests\Domain\Twitter;

use App\Domain\Twitter\TwitterProfile;

class TwitterProfileTest extends \App\Tests\BaseUnitTest
{
    private $accessToken = 'oauth-token';

    private $accessSecret = 'oauth-secret';
    
    /** @test */
    public function is_constructed_with_a_username_and_description()
    {
        $expectedUsername = 'foo';
        $expectedDesc = 'bar';

        $account = new TwitterProfile($expectedUsername, $expectedDesc);

        $this->assertEquals($expectedUsername, $account->getUsername());
        $this->assertEquals($expectedDesc, $account->getDescription());
    }

    /** @test */
    public function sets_and_retrieves_its_description()
    {
        $expectedDesc = 'new Description';
        $account = new TwitterProfile('foo', 'desc');

        $account->setDescription($expectedDesc);

        $this->assertEquals($expectedDesc, $account->getDescription());
    }

    /** @test */
    public function sets_and_retrieves_its_oauth_credentials()
    {
        $account = (new TwitterProfile('foo', 'bar'))
            ->setAccessCredentials($this->accessToken, $this->accessSecret);

        $this->assertEquals($this->accessToken, $account->getAccessToken());
        $this->assertEquals($this->accessSecret, $account->getAccessSecret());
    }

    /** @test */
    public function determines_if_it_has_all_required_credentials()
    {
        $full = (new TwitterProfile('foo', 'bar'))
            ->setAccessCredentials($this->accessToken, $this->accessSecret);
        $none = new TwitterProfile('foo', 'bar');

        $this->assertTrue($full->hasCredentials());
        $this->assertFalse($none->hasCredentials());
    }

    /** @test */
    public function can_be_created_with_and_retrieve_its_allowed_categories()
    {
        $expectedCategories = ['Foo', 'Bar'];
        $profile = new TwitterProfile('username', 'desc', '', '', $expectedCategories);

        $actualCategories = $profile->getAllowedCategories();

        $this->assertEquals($expectedCategories, $actualCategories);
    }

    /** @test */
    public function checks_whether_it_has_an_allowed_category()
    {
        $profile = new TwitterProfile('username', 'desc', '', '', ['Foo', 'Bar']);

        $this->assertTrue( $profile->hasAllowedCategory('Foo') );
        $this->assertFalse( $profile->hasAllowedCategory('Baz') );
    }

    /** @test */
    public function sets_its_allowed_categories()
    {
        $expectedCategories = ['Foo', 'Bar'];
        $profile = new TwitterProfile('username', 'desc');

        $profile->setAllowedCategories($expectedCategories);
        $actualCategories = $profile->getAllowedCategories();

        $this->assertEquals($expectedCategories, $actualCategories);

    }
}