Adds array access interface to presenter class and supporting unit tests (#17)

* Adds array access interface to presenter class and supporting unit tests.

* Updates unit test to use annotation based exception expectation.

Author: robinmalburn

src/Presenter.php

@@ -5,8 +5,10 @@
 use Illuminate\Support\Str;
 use Illuminate\Contracts\Support\Jsonable;
 use Illuminate\Contracts\Support\Arrayable;
+use ArrayAccess;
+use BadMethodCallException;
 
-abstract class Presenter implements Jsonable, Arrayable
+abstract class Presenter implements Jsonable, Arrayable, ArrayAccess
 {
     /**
      * The attributes that should be visible in arrays.
@@ -261,4 +263,66 @@ protected function getArrayableItems($values)
 
         return $values;
     }
-}
+
+     /**
+     * Return true if the property is set and not null.
+     *
+     * @param string $name
+     * @return bool
+     */
+    public function __isset($name)
+    {
+        return $this->offsetExists($name);
+    }
+
+    /**
+     * Return true if the offset exists and is not null.
+     *
+     * @param mixed $offset
+     * @return bool
+     */
+    public function offsetExists($offset)
+    {
+        return $this->{$offset} !== null;
+    }
+
+    /**
+     * Return the value at the specified offset.
+     *
+     * @param mixed $offset
+     * @return mixed
+     */
+    public function offsetGet($offset)
+    {
+        return $this->{$offset};
+    }
+
+    /**
+     * Required implementation to satisfy the ArrayAccess interface,
+     * but throws as a BadMethodCallException as this is a read only
+     * implementation.
+     *
+     * @param mixed $offset
+     * @param mixed $value
+     * @return void
+     * @throws \BadMethodCallException
+     */
+    public function offsetSet($offset, $value)
+    {
+        throw new BadMethodCallException('Not implemented - read only implementation.');
+    }
+
+    /**
+     * Required implementation to satisfy the ArrayAccess interface,
+     * but throws as a BadMethodCallException as this is a read only
+     * implementation.
+     *
+     * @param mixed $offset
+     * @return void
+     * @throws \BadMethodCallException
+     */
+    public function offsetUnset($offset)
+    {
+        throw new BadMethodCallException('Not implemented - read only implementation.');
+    }
+}

tests/PresenterTest.php

@@ -213,6 +213,23 @@ public function you_can_transform_a_collection_of_eloquent_models()
         $this->assertEquals('David Lee Hemphill', $firstUser->full_name);
     }
 
+    /** @test */
+    public function you_can_access_a_collection_of_eloquent_models()
+    {
+        $sampleModel = $this->createModel();
+
+        $users = collect([$sampleModel])->present(SamplePresenter::class);
+
+        $this->assertEquals(
+            collect(['David']),
+            $users->pluck('first_name')
+        );
+
+        $this->assertEquals(
+            collect(['David Lee Hemphill']),
+            $users->pluck('full_name'));
+    }
+
     /** @test */
     public function you_can_present_a_collection_of_models_using_a_closure()
     {
@@ -497,6 +514,41 @@ public function a_presenter_can_specify_attributes_to_show_in_json_or_array_outp
 
         $this->assertEquals($desired, (string) $presentedModel);
     }
+
+    /** @test */
+    public function it_can_be_array_accessed()
+    {
+        $sampleModel = TestModel::create([
+            'first_name' => 'David',
+            'last_name' => 'Hemphill',
+            'created_at' => '2015-10-14 12:00:00',
+            'updated_at' => '2015-10-14 12:00:00',
+        ]);
+
+        $presenter = $sampleModel->present(SamplePresenter::class);
+
+        $this->assertEquals('David', $presenter['first_name']);
+
+        $this->assertEquals('David Lee Hemphill', $presenter['full_name']);
+    }
+
+    /**
+     * @test 
+     * @expectedException BadMethodCallException
+     * */
+    public function it_cannot_be_written_to_via_array_access()
+    {
+        $sampleModel = TestModel::create([
+            'first_name' => 'David',
+            'last_name' => 'Hemphill',
+            'created_at' => '2015-10-14 12:00:00',
+            'updated_at' => '2015-10-14 12:00:00',
+        ]);
+
+        $presenter = $sampleModel->present(SamplePresenter::class);
+
+        $presenter['first_name'] = 'should not update';
+    }
 }
 
 class TestModel extends Model