Assert Laravel Package

Getting Started

Start by installing the package via Composer:

composer require --dev zenstruck/assert

Then, import and use the Assert class in your tests or application code:

use function Zenstruck\Assert\assert;

assert($user->isActive())->true();
assert($user->getEmail())->email()->notBlank();
assert($items)->count(3);

The README and src/ directory contain the full API reference — begin with assert(), assertNotNull(), and Assert::that() factory methods.

Implementation Patterns

• In Tests: Replace verbose assertEquals(), assertTrue() calls with chainable assertions for intent clarity:

  assert($response->getStatusCode())->eq(200);
  assert($response->json('data.user'))->hasKey('email')->and()->email();
  

• Runtime Validation: Wrap domain logic with assertions for fail-fast behavior:

  assert($order->total())->greaterThan(0);
  assert($product->stock())->greaterThanOrEqualTo($requestedQuantity);
  

• Fluent Chaining: Combine assertions for complex conditions:

  assert($payload)->isArray()->hasKey('id')->and()->isInt()->greaterThan(0);
  

• Integration with PHPUnit: Works out-of-the-box — no special setup required; assertions throw AssertionFailedError.

Gotchas and Tips

• Namespace Tip: Use use function Zenstruck\Assert\assert; to enable assert(...) without class resolution — avoid naming conflicts with PHP’s built-in assert().
• Debugging: When an assertion fails, the message includes the expected, actual, and description — always provide context via assert($value, 'User email must be verified')->email();
• Custom Messages: Pass a third argument for dynamic context:

  assert($result, 'Must contain valid product', "Expected product '{$productId}' to exist");
  

• Exhaustive Testing: Use collection assertions like each(), all(), and hasKey() for arrays/objects to validate complex structures.
• Extensibility: While the package is small, you can extend with your own Assertion subclasses for domain-specific checks (e.g., assert()->isStripeId()).