add duckduckgo images engine

tests/unit/engines/test_duckduckgo_images.py

@@ -0,0 +1,72 @@
+# -*- coding: utf-8 -*-
+from collections import defaultdict
+import mock
+from searx.engines import duckduckgo_images
+from searx.testing import SearxTestCase
+
+
+class TestDuckduckgoImagesEngine(SearxTestCase):
+
+    def test_request(self):
+        query = 'test_query'
+        dicto = defaultdict(dict)
+        dicto['is_test'] = True
+        dicto['pageno'] = 1
+        dicto['safesearch'] = 0
+        dicto['language'] = 'all'
+        params = duckduckgo_images.request(query, dicto)
+        self.assertIn('url', params)
+        self.assertIn(query, params['url'])
+        self.assertIn('duckduckgo.com', params['url'])
+        self.assertIn('s=0', params['url'])
+        self.assertIn('p=-1', params['url'])
+        self.assertIn('vqd=12345', params['url'])
+
+        # test paging and safe search
+        dicto['pageno'] = 2
+        dicto['safesearch'] = 2
+        params = duckduckgo_images.request(query, dicto)
+        self.assertIn('url', params)
+        self.assertIn(query, params['url'])
+        self.assertIn('s=50', params['url'])
+        self.assertIn('p=1', params['url'])
+
+    def test_response(self):
+        self.assertRaises(AttributeError, duckduckgo_images.response, None)
+        self.assertRaises(AttributeError, duckduckgo_images.response, [])
+        self.assertRaises(AttributeError, duckduckgo_images.response, '')
+        self.assertRaises(AttributeError, duckduckgo_images.response, '[]')
+
+        response = mock.Mock(text='If this error persists, please let us know: ops@duckduckgo.com')
+        self.assertEqual(duckduckgo_images.response(response), [])
+
+        json = u"""
+        {
+            "query": "test_query",
+            "results": [
+                {
+                    "title": "Result 1",
+                    "url": "https://site1.url",
+                    "thumbnail": "https://thumb1.nail",
+                    "image": "https://image1"
+                },
+                {
+                    "title": "Result 2",
+                    "url": "https://site2.url",
+                    "thumbnail": "https://thumb2.nail",
+                    "image": "https://image2"
+                }
+            ]
+        }
+        """
+        response = mock.Mock(text=json)
+        results = duckduckgo_images.response(response)
+        self.assertEqual(len(results), 2)
+        self.assertEqual(results[0]['title'], 'Result 1')
+        self.assertEqual(results[0]['url'], 'https://site1.url')
+        self.assertEqual(results[0]['thumbnail_src'], 'https://thumb1.nail')
+        self.assertEqual(results[0]['img_src'], 'https://image1')
+        self.assertEqual(results[1]['title'], 'Result 2')
+        self.assertEqual(results[1]['url'], 'https://site2.url')
+        self.assertEqual(results[1]['thumbnail_src'], 'https://thumb2.nail')
+        self.assertEqual(results[1]['img_src'], 'https://image2')