PHP7 Static Factory

Author: Dominik Liebler

Creational/StaticFactory/StaticFactory.php

@@ -3,30 +3,26 @@
 namespace DesignPatterns\Creational\StaticFactory;
 
 /**
- * Note1: Remember, static => global => evil
+ * Note1: Remember, static means global state which is evil because it can't be mocked for tests
  * Note2: Cannot be subclassed or mock-upped or have multiple different instances.
  */
-class StaticFactory
+final class StaticFactory
 {
     /**
-     * the parametrized function to get create an instance.
-     *
      * @param string $type
      *
-     * @static
-     *
-     * @throws \InvalidArgumentException
-     *
      * @return FormatterInterface
      */
-    public static function factory($type)
+    public static function factory(string $type): FormatterInterface
     {
-        $className = __NAMESPACE__.'\Format'.ucfirst($type);
+        if ($type == 'number') {
+            return new FormatNumber();
+        }
 
-        if (!class_exists($className)) {
-            throw new \InvalidArgumentException('Missing format class.');
+        if ($type == 'string') {
+            return new FormatString();
         }
 
-        return new $className();
+        throw new \InvalidArgumentException('Unknown format given');
     }
 }

Creational/StaticFactory/Tests/StaticFactoryTest.php

@@ -4,33 +4,29 @@
 
 use DesignPatterns\Creational\StaticFactory\StaticFactory;
 
-/**
- * Tests for Static Factory pattern.
- */
 class StaticFactoryTest extends \PHPUnit_Framework_TestCase
 {
-    public function getTypeList()
+    public function testCanCreateNumberFormatter()
     {
-        return array(
-            array('string'),
-            array('number'),
+        $this->assertInstanceOf(
+            'DesignPatterns\Creational\StaticFactory\FormatNumber',
+            StaticFactory::factory('number')
         );
     }
 
-    /**
-     * @dataProvider getTypeList
-     */
-    public function testCreation($type)
+    public function testCanCreateStringFormatter()
     {
-        $obj = StaticFactory::factory($type);
-        $this->assertInstanceOf('DesignPatterns\Creational\StaticFactory\FormatterInterface', $obj);
+        $this->assertInstanceOf(
+            'DesignPatterns\Creational\StaticFactory\FormatString',
+            StaticFactory::factory('string')
+        );
     }
 
     /**
-     * @expectedException InvalidArgumentException
+     * @expectedException \InvalidArgumentException
      */
     public function testException()
     {
-        StaticFactory::factory('');
+        StaticFactory::factory('object');
     }
 }