update file history page/api

1. user with `r` and `rw` permission can view file history
2. add new file history api

tests/api/endpoints/test_file_history.py

@@ -0,0 +1,41 @@
+import json
+
+from django.core.urlresolvers import reverse
+
+from seahub.test_utils import BaseTestCase
+from tests.common.utils import randstring
+
+class FileHistoryTest(BaseTestCase):
+
+    def setUp(self):
+
+        self.endpoint = reverse('api-v2.1-file-history-view', args=[self.repo.id])
+        self.username = self.user.username
+
+    def tearDown(self):
+        self.remove_repo()
+
+    def test_can_get(self):
+        self.login_as(self.user)
+        file_path = self.file
+        resp = self.client.get(self.endpoint + "?path=%s" % file_path)
+        self.assertEqual(200, resp.status_code)
+        json_resp = json.loads(resp.content)
+        assert json_resp['data'][0]['path'] == file_path
+        assert json_resp['data'][0]['creator_email'] == self.user.username
+
+    def test_can_get_with_invalid_path_parameter(self):
+        self.login_as(self.user)
+        resp = self.client.get(self.endpoint)
+        self.assertEqual(400, resp.status_code)
+
+    def test_can_get_with_invalid_user_permission(self):
+        self.login_as(self.admin)
+        file_path = self.file
+        resp = self.client.get(self.endpoint + "?path=%s" % file_path)
+        self.assertEqual(403, resp.status_code)
+
+    def test_can_get_with_invalid_file(self):
+        self.login_as(self.admin)
+        resp = self.client.get(self.endpoint + "?path=%s" % randstring(6))
+        self.assertEqual(404, resp.status_code)