Double: Mock PHP Classes in Tests With One API | Mohamed Said [Skip to content](#main) [ ![](https://cdn.msaied.com/01KT78WE565VEMM3PSNQAAB0MH.png) Mohamed SaidLaravel Backend Engineer ](https://www.msaied.com/public) - [Home](https://www.msaied.com/public) - [Projects](https://www.msaied.com/public/projects) - [Articles](https://www.msaied.com/public/articles) - [Certificates](https://www.msaied.com/public/certificates) - [About](https://www.msaied.com/public#about) [ Contact](https://www.msaied.com/public#contact) Menu Menu ---- Close - [HomeStart here](https://www.msaied.com/public) - [ProjectsCase studies](https://www.msaied.com/public/projects) - [ArticlesEngineering notes](https://www.msaied.com/public/articles) - [CertificatesCredentials](https://www.msaied.com/public/certificates) - [AboutHow I work](https://www.msaied.com/public#about) - [ContactGet in touch](https://www.msaied.com/public#contact) [Start a conversation](https://www.msaied.com/public#contact) [WhatsApp](https://wa.me/201094619204) [Email](mailto:hello@msaied.com) 1. [Home](https://www.msaied.com/public) 2. / 3. [Articles](https://www.msaied.com/public/articles) 4. / 5. [Composer Pacakge](https://www.msaied.com/public/articles?category=composer-pacakge) 6. / 7. Mock PHP Classes in Tests With the Double Library [Composer Pacakge](https://www.msaied.com/public/articles?category=composer-pacakge) [PHP](https://www.msaied.com/public/articles?category=php) Mock PHP Classes in Tests With the Double Library ================================================== Double is a PHP 8.3 test double library by Jason McCreary that replaces mocks, spies, and partials with a single unified API — one constructor, three modes, and two setup verbs. ![](https://cdn.msaied.com/01M22N44A70A5MC2S599JP0MPH.webp) [Mohamed Said](https://www.msaied.com/public#person) Published 11 Aug 2026 · Updated 11 Aug 2026 · 4 min read ShareCopy linkCopied ![Mock PHP Classes in Tests With the Double Library](https://cdn.msaied.com/537/be45e68dffd72aa9bd833c2f409fcb07.png) On this page +1. [What Is the Double Library?](#what-is-the-double-library) 2. [Creating a Double](#creating-a-double) 3. [Three Modes](#three-modes) 4. [Expectations and Argument Matching](#expectations-and-argument-matching) 5. [Verification](#verification) 6. [Failure Messages](#failure-messages) 7. [Migrating From Mockery](#migrating-from-mockery) 8. [Key Takeaways](#key-takeaways) What Is the Double Library? --------------------------- [Double](https://github.com/jasonmccreary/double) is a PHP 8.3 test double library by Jason McCreary, the creator of Laravel Shift. Instead of choosing between a mock, a spy, and a partial at creation time, you create one kind of object — a *double* — and the verbs you use afterward determine how it behaves. The package is at v0.4.0 and works with PHPUnit 11 and 12 as well as Pest. Install it as a dev dependency: ```bash composer require --dev jasonmccreary/double ``` No service provider or configuration file is needed. Creating a Double ----------------- `Double::for()` accepts a class name, an interface, multiple interfaces, or a real instance: ```php use JMac\Testing\Double; $repository = Double::for(BookRepository::class); $logger = Double::for(LoggerInterface::class, FlushableInterface::class); ``` The returned object satisfies `instanceof` and any type hint expecting the target, so it drops straight into a constructor without casting. Three Modes ----------- | Mode | Behaviour on unconfigured calls | |---|---| | **Loose** (default) | Returns a type-safe value (`false`, `0`, `[]`, a fresh double, etc.) | | **Strict** | Throws immediately | | **Passthru** | Delegates to a real instance and still records every call | ```php $repository = Double::for(BookRepository::class)->strict(); $logger = Double::for(Logger::class)->passthru($realLogger); ``` Expectations and Argument Matching ---------------------------------- Two verbs cover all setup: `expects()` (must be called) and `allows()` (may be called). ```php $repository->expects('find')->with(123)->returns($book); $repository->allows('find')->with(999)->throws(new NotFoundException()); $repository->allows('calculateTax')->resolves(fn (...$args) => $gateway->calculateTax(...$args)); ``` Call counts use a single `times()` method with named arguments instead of Mockery's chained helpers: ```php $repository->expects('save'); // exactly once $repository->expects('save')->times(2); // exactly twice $repository->expects('save')->times(1, 3); // between 1 and 3 $repository->expects('save')->times(minimum: 2); // at least 2 $repository->allows('save')->times(maximum: 5); // at most 5 $repository->allows('save')->never(); // zero calls ``` The `Argument` facade handles looser matching: ```php use JMac\Testing\Matching\Argument; $repository->allows('save')->with(Argument::type(Book::class))->returns(true); $repository->allows('find')->with(Argument::any(1, 2, 3))->returns($book); $repository->allows('saveAll')->with(Argument::contains($book))->returns(true); ``` `Argument::capture($var)` writes the real argument into a variable for further assertions. `Argument::not()` negates any matcher without nesting. Verification ------------ Call `verify()` at the end of a test, or add the `VerifiesDoubles` trait to your base test case and let it run automatically: ```php use JMac\Testing\Integrations\PHPUnit\VerifiesDoubles; class TestCase extends \PHPUnit\Framework\TestCase { use VerifiesDoubles; } ``` `received()` checks after the fact on any double — no spy declaration required: ```php $repository->received('recordView')->with($book); $repository->received('save')->times(2); $repository->received('delete')->never(); ``` `unused()` asserts a double received zero calls to any method and lists every call it actually saw. Failure Messages ---------------- Double names the class you doubled (not a generated identifier), and on an unmet expectation it lists what the method was actually called with: ```javascript Double `foo` expected `find('baz')` to be called exactly 1 time, but it was never called. The following calls to `find` were made during this test: `find('Baz')` ``` A typo in a method name is caught at configuration time, not at the end of the test, and a "did you mean" suggestion is included when something close exists. Migrating From Mockery ---------------------- The docs include a full method-by-method mapping. The most common conversions: - `Mockery::mock(Foo::class)` → `Double::for(Foo::class)` - `shouldReceive('foo')->once()->andReturn($x)` → `expects('foo')->returns($x)` - `shouldHaveReceived('foo')` → `received('foo')` - `Mockery::close()` → `verify()` or the `VerifiesDoubles` trait A free [Double Converter](https://laravelshift.com/mockery-test-double-converter) from Laravel Shift automates the migration. Key Takeaways ------------- - One constructor (`Double::for()`) replaces mock, spy, and partial decisions. - `expects()` and `allows()` are the only setup verbs; `times()` with named arguments handles all count shapes. - Loose mode returns type-safe defaults so tests don't break on unconfigured calls. - `received()` provides spy-style post-hoc assertions on every double. - PHPUnit integration turns failures into proper assertion failures and the `VerifiesDoubles` trait removes manual `verify()` calls. - Requires PHP 8.3; works inside or outside Laravel with PHPUnit 11/12 or Pest. Full documentation is at [testdoublephp.com](https://testdoublephp.com/). --- *Source: [Mock PHP Classes in Tests With the Double Library — Laravel News](https://laravel-news.com/double-php-testing-library)* - [testing](https://www.msaied.com/public/articles?search=testing) - [mocking](https://www.msaied.com/public/articles?search=mocking) - [phpunit](https://www.msaied.com/public/articles?search=phpunit) - [php](https://www.msaied.com/public/articles?search=php) - [laravel](https://www.msaied.com/public/articles?search=laravel) - [packages](https://www.msaied.com/public/articles?search=packages) Frequently asked questions --------------------------- How does Double differ from Mockery in PHP tests?Double uses a single `Double::for()` constructor instead of separate mock/spy/partial factories. Setup uses only two verbs — `expects()` and `allows()` — and spy-style `received()` checks are available on every double without declaring a spy upfront. There is no `Mockery::close()` equivalent; you call `verify()` or use the `VerifiesDoubles` trait instead. What PHP version does the Double library require?Double requires PHP 8.3 or higher. It works with PHPUnit 11 and 12 as well as Pest, inside or outside a Laravel application. Can I migrate an existing Mockery test suite to Double automatically?Yes. The Double documentation includes a full method-by-method mapping from Mockery to Double, and Laravel Shift provides a free Double Converter tool that automates the conversion. ![Mohamed Said](https://cdn.msaied.com/01M22N44A70A5MC2S599JP0MPH.webp)About the author ---------------- [Mohamed Said](https://www.msaied.com/public#person)Senior Backend Engineer specializing in Laravel, scalable SaaS platforms, APIs, and cloud infrastructure. I build secure, high-performance web applications that help businesses grow. [About](https://www.msaied.com/public#about) [GitHub ↗](https://github.com/EG-Mohamed) [LinkedIn ↗](https://www.linkedin.com/in/msaiedm/) [WhatsApp ↗](https://wa.me/201094619204) [Email Address ↗](mailto:hello@msaied.com) [My CV ↗](https://drive.google.com/file/u/0/d/1MF20IPRJyzfy32mhEutjL5EpSls0w2Q8/view) [Previous articleCursor Pagination and Lazy Collections at Scale in Laravel](https://www.msaied.com/public/articles/cursor-pagination-and-lazy-collections-at-scale-in-laravel) [Next articleNightOwl: Laravel Monitoring With Flat Pricing and Your Own PostgreSQL Storage](https://www.msaied.com/public/articles/nightowl-laravel-monitoring-with-flat-pricing-and-your-own-postgresql-storage) On this page ------------- 1. [What Is the Double Library?](#what-is-the-double-library) 2. [Creating a Double](#creating-a-double) 3. [Three Modes](#three-modes) 4. [Expectations and Argument Matching](#expectations-and-argument-matching) 5. [Verification](#verification) 6. [Failure Messages](#failure-messages) 7. [Migrating From Mockery](#migrating-from-mockery) 8. [Key Takeaways](#key-takeaways) ### Have a technical challenge? Tell me what you’re building. I reply within two working days. 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