feat: move Expectations API out of external plugin

tests/Features/Expect/HigherOrder/methodsAndProperties.php

@@ -0,0 +1,50 @@
+<?php
+
+it('can access methods and properties', function () {
+    expect(new HasMethodsAndProperties())
+        ->name->toEqual('Has Methods and Properties')->not()->toEqual('bar')
+        ->multiply(3, 4)->not->toBeString->toEqual(12)
+        ->posts->each(function ($post) {
+            $post->is_published->toBeTrue;
+        })->books()->toBeArray()
+        ->posts->toBeArray->each->not->toBeEmpty
+        ->books()->sequence(
+            function ($book) { $book->title->toEqual('Foo')->cost->toEqual(20); },
+            function ($book) { $book->title->toEqual('Bar')->cost->toEqual(30); },
+        );
+});
+
+class HasMethodsAndProperties
+{
+    public $name = 'Has Methods and Properties';
+
+    public $posts = [
+        [
+            'is_published' => true,
+            'title'        => 'Foo',
+        ],
+        [
+            'is_published' => true,
+            'title'        => 'Bar',
+        ],
+    ];
+
+    public function books()
+    {
+        return [
+            [
+                'title' => 'Foo',
+                'cost'  => 20,
+            ],
+            [
+                'title' => 'Bar',
+                'cost'  => 30,
+            ],
+        ];
+    }
+
+    public function multiply($x, $y)
+    {
+        return $x * $y;
+    }
+}