implements decorators pipeline

src/Concerns/Extendable.php

@@ -17,6 +17,9 @@ trait Extendable
      */
     private static $extends = [];
 
+    /** @var array<string, array<Closure>> */
+    private static $decorators = [];
+
     /**
      * Register a custom extend.
      */
@@ -25,6 +28,11 @@ trait Extendable
         static::$extends[$name] = $extend;
     }
 
+    public static function decorate(string $name, Closure $decorator): void
+    {
+        static::$decorators[$name][] = $decorator;
+    }
+
     /**
      * Checks if extend is registered.
      */
@@ -33,6 +41,32 @@ trait Extendable
         return array_key_exists($name, static::$extends);
     }
 
+    /**
+     * Checks if decorator are registered.
+     */
+    public static function hasDecorators(string $name): bool
+    {
+        return array_key_exists($name, static::$decorators);
+    }
+
+    /**
+     * @return array<int, Closure>
+     */
+    public function decorators(string $name, object $context, string $scope): array
+    {
+        if (!self::hasDecorators($name)) {
+            return [];
+        }
+
+        $decorators = [];
+        foreach (self::$decorators[$name] as $decorator) {
+            //@phpstan-ignore-next-line
+            $decorators[] = $decorator->bindTo($context, $scope);
+        }
+
+        return $decorators;
+    }
+
     /**
      * Dynamically handle calls to the class.
      *

src/Expectation.php

@@ -7,6 +7,7 @@ namespace Pest;
 use BadMethodCallException;
 use Pest\Concerns\Extendable;
 use Pest\Concerns\RetrievesValues;
+use Pest\Support\Pipeline;
 use PHPUnit\Framework\Assert;
 use PHPUnit\Framework\ExpectationFailedException;
 
@@ -250,23 +251,50 @@ final class Expectation
      *
      * @param array<int, mixed> $parameters
      *
-     * @return HigherOrderExpectation|mixed
+     * @return HigherOrderExpectation|Expectation
      */
     public function __call(string $method, array $parameters)
     {
-        if (method_exists($this->coreExpectation, $method)) {
+        if (!$this->hasExpectation($method)) {
-            //@phpstan-ignore-next-line
-            $this->coreExpectation = $this->coreExpectation->{$method}(...$parameters);
-
-            return $this;
-        }
-
-        if (!self::hasExtend($method)) {
             /* @phpstan-ignore-next-line */
             return new HigherOrderExpectation($this, $this->value->$method(...$parameters));
         }
 
-        return $this->__extendsCall($method, $parameters);
+        Pipeline::send(...$parameters)
+            ->through($this->decorators($method, $this, Expectation::class))
+            ->finally(function ($parameters) use ($method): void {
+                $this->callExpectation($method, $parameters);
+            });
+
+        return $this;
+    }
+
+    /**
+     * @param array<mixed> $parameters
+     */
+    private function callExpectation(string $name, array $parameters): void
+    {
+        if (method_exists($this->coreExpectation, $name)) {
+            //@phpstan-ignore-next-line
+            $this->coreExpectation->{$name}(...$parameters);
+        } else {
+            if (self::hasExtend($name)) {
+                $this->__extendsCall($name, $parameters);
+            }
+        }
+    }
+
+    private function hasExpectation(string $name): bool
+    {
+        if (method_exists($this->coreExpectation, $name)) {
+            return true;
+        }
+
+        if (self::hasExtend($name)) {
+            return true;
+        }
+
+        return false;
     }
 
     /**

src/Support/Extendable.php

@@ -30,4 +30,9 @@ final class Extendable
     {
         $this->extendableClass::extend($name, $extend);
     }
+
+    public function decorate(string $name, Closure $extend): void
+    {
+        $this->extendableClass::decorate($name, $extend);
+    }
 }

src/Support/Pipeline.php

@@ -0,0 +1,69 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Pest\Support;
+
+use Closure;
+
+final class Pipeline
+{
+    /** @var array<Closure> */
+    private $pipes = [];
+
+    /** @var array<mixed> */
+    private $passable;
+
+    /**
+     * @param array<mixed> $passable
+     */
+    public function __construct(...$passable)
+    {
+        $this->passable = $passable;
+    }
+
+    /**
+     * @param array<mixed> $passable
+     */
+    public static function send(...$passable): self
+    {
+        return new self(...$passable);
+    }
+
+    /**
+     * @param array<Closure> $pipes
+     */
+    public function through(array $pipes): self
+    {
+        $this->pipes = $pipes;
+
+        return $this;
+    }
+
+    public function finally(Closure $finalClosure): void
+    {
+        $pipeline = array_reduce(
+            array_reverse($this->pipes),
+            $this->carry(),
+            $this->prepareFinalClosure($finalClosure)
+        );
+
+        $pipeline(...$this->passable);
+    }
+
+    public function carry(): Closure
+    {
+        return function ($stack, $pipe): Closure {
+            return function (...$passable) use ($stack, $pipe) {
+                return $pipe($stack, ...$passable);
+            };
+        };
+    }
+
+    private function prepareFinalClosure(Closure $finalClosure): Closure
+    {
+        return function (...$passable) use ($finalClosure) {
+            return $finalClosure($passable);
+        };
+    }
+}

tests/Features/Expect/HigherOrder/decorate.php

@@ -0,0 +1,56 @@
+<?php
+
+use function PHPUnit\Framework\assertEquals;
+use function PHPUnit\Framework\assertInstanceOf;
+
+class Number
+{
+    public $value;
+
+    public function __construct($value)
+    {
+        $this->value = $value;
+    }
+}
+
+class Character
+{
+    public $value;
+
+    public function __construct($value)
+    {
+        $this->value = $value;
+    }
+}
+
+expect()->decorate('toBe', function ($next, $expected) {
+    if ($this->value instanceof Character) {
+        assertInstanceOf(Character::class, $expected);
+        assertEquals($this->value->value, $expected->value);
+
+        return;
+    }
+
+    $next($expected);
+});
+
+expect()->decorate('toBe', function ($next, $expected) {
+    if ($this->value instanceof Number) {
+        assertInstanceOf(Number::class, $expected);
+        assertEquals($this->value->value, $expected->value);
+
+        return;
+    }
+
+    $next($expected);
+});
+
+test('pass', function () {
+    $number = new Number(1);
+
+    $letter = new Character('A');
+
+    expect($number)->toBe(new Number(1));
+    expect($letter)->toBe(new Character('A'));
+    expect(3)->toBe(3);
+});