- added arrayaccess to readonly document

- added tests for arrayaccess implementation

library/Solarium/Document/ReadOnly.php

@@ -44,7 +44,8 @@
  * @package Solarium
  * @subpackage Document
  */
-class Solarium_Document_ReadOnly implements IteratorAggregate, Countable
+class Solarium_Document_ReadOnly
+    implements IteratorAggregate, Countable, ArrayAccess
 {
 
     /**
@@ -129,4 +130,45 @@ class Solarium_Document_ReadOnly implements IteratorAggregate, Countable
         return count($this->_fields);
     }
 
+    /**
+     * ArrayAccess implementation
+     *
+     * @param miex $offset
+     * @param mixed $value
+     * @return void
+     */
+    public function offsetSet($offset, $value) {
+        $this->__set($offset, $value);
+    }
+
+    /**
+     * ArrayAccess implementation
+     *
+     * @param mixed $offset
+     * @return bool
+     */
+    public function offsetExists($offset) {
+        return isset($this->_fields[$offset]);
+    }
+
+    /**
+     * ArrayAccess implementation
+     *
+     * @param mixed $offset
+     * @return void
+     */
+    public function offsetUnset($offset) {
+        $this->__set($offset, null);
+    }
+
+    /**
+     * ArrayAccess implementation
+     *
+     * @param mixed $offset
+     * @return mixed|null
+     */
+    public function offsetGet($offset) {
+        return isset($this->_fields[$offset]) ? $this->_fields[$offset] : null;
+    }
+
 }
\ No newline at end of file

tests/Solarium/Document/ReadOnlyTest.php

@@ -83,6 +83,48 @@ class Solarium_Document_ReadOnlyTest extends PHPUnit_Framework_TestCase
         $this->assertEquals($this->_fields, $fields);
     }
 
+    public function testArrayGet()
+    {
+        $this->assertEquals(
+            $this->_fields['categories'],
+            $this->_doc['categories']
+        );
+    }
+
+    public function testArrayGetInvalidField()
+    {
+        $this->assertEquals(
+            null,
+            $this->_doc['invalidfield']
+        );
+    }
+
+    public function testArrayIsset()
+    {
+        $this->assertTrue(
+            isset($this->_doc['categories'])
+        );
+    }
+
+    public function testArrayIssetInvalidField()
+    {
+        $this->assertFalse(
+            isset($this->_doc['invalidfield'])
+        );
+    }
+
+    public function testArraySet()
+    {
+        $this->setExpectedException('Solarium_Exception');
+        $this->_doc['newField'] = 'new value';
+    }
+
+    public function testArrayUnset()
+    {
+        $this->setExpectedException('Solarium_Exception');
+        unset($this->_doc['newField']);
+    }
+
     public function testCount()
     {
         $this->assertEquals(count($this->_fields), count($this->_doc));