Added geo bounding box filter

Filter/GeoBoundingBoxFilterTest.php

+<?php
+
+/*
+ * This file is part of the ONGR package.
+ *
+ * (c) NFQ Technologies UAB <info@nfq.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace ONGR\ElasticsearchBundle\Tests\Unit\DSL\Filter;
+
+use ONGR\ElasticsearchBundle\DSL\Filter\GeoBoundingBoxFilter;
+
+class GeoBoundingBoxFilterTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * Test if exception is thrown when geo points are not set.
+     *
+     * @expectedException \LogicException
+     */
+    public function testGeoBoundBoxFilterException()
+    {
+        $filter = new GeoBoundingBoxFilter('location', []);
+        $filter->toArray();
+    }
+}