create a Test folder for each pattern

Behavioral/Observer/Tests/ObserverTest.php

@@ -0,0 +1,61 @@
+<?php
+
+namespace DesignPatterns\Behavioral\Observer\Tests;
+
+use DesignPatterns\Behavioral\Observer\UserObserver;
+use DesignPatterns\Behavioral\Observer\User;
+
+/**
+ * ObserverTest tests the Observer pattern
+ */
+class ObserverTest extends \PHPUnit_Framework_TestCase
+{
+
+    protected $observer;
+
+    protected function setUp()
+    {
+        $this->observer = new UserObserver();
+    }
+
+    /**
+     * Tests the notification
+     */
+    public function testNotify()
+    {
+        $this->expectOutputString('DesignPatterns\Behavioral\Observer\User has been updated');
+        $subject = new User();
+
+        $subject->attach($this->observer);
+        $subject->property = 123;
+    }
+
+    /**
+     * Tests the subscribing
+     */
+    public function testAttachDetach()
+    {
+        $subject = new User();
+        $this->assertAttributeEmpty('observers', $subject);
+        $subject->attach($this->observer);
+        $this->assertAttributeNotEmpty('observers', $subject);
+        $subject->detach($this->observer);
+        $this->assertAttributeEmpty('observers', $subject);
+    }
+
+    /**
+     * Tests the update() invocation on a mockup
+     */
+    public function testUpdateCalling()
+    {
+        $subject = new User();
+        $observer = $this->getMock('SplObserver');
+        $subject->attach($observer);
+
+        $observer->expects($this->once())
+            ->method('update')
+            ->with($subject);
+
+        $subject->notify();
+    }
+}