implements decorators pipeline

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);
+});