Allow to search user in admin by email

As a fallback for when searching by username did not return any results.

h/admin.py

@@ -172,10 +172,12 @@ def users_index(request):
     user_meta = {}
     username = request.params.get('username')
 
-    if username is not None:
+    if username:
         user = models.User.get_by_username(username)
+        if not user:
+            user = models.User.get_by_email(username)
 
-    if user is not None:
+    if user:
         # Fetch information on how many annotations the user has created
         userid = util.userid_from_username(username, request)
         query = _all_user_annotations_query(userid)

h/templates/admin/users.html.jinja2

@@ -10,7 +10,7 @@
 
   <form method="GET" class="form-inline">
     <div class="form-group">
-      <label for="username">Username</label>
+      <label for="username">Username or email</label>
       <input type="text" class="form-control" name="username">
       <input type="submit" class="btn btn-default" value="Find">
     </div>
@@ -44,7 +44,7 @@
         </tbody>
       </table>
     {% else %}
-      <p>No user found with username <em>{{ username }}</em>!</p>
+      <p>No user found with username or email <em>{{ username }}</em>!</p>
     {% endif %}
   {% endif %}
 {% endblock %}

h/test/admin_test.py

@@ -451,6 +451,18 @@ def test_users_index_looks_up_users_by_username(User):
 
     User.get_by_username.assert_called_with("bob")
 
+@users_index_fixtures
+def test_users_index_looks_up_users_by_email(User):
+    es = MagicMock()
+    request = DummyRequest(params={"username": "bob@builder.com"},
+                           es=es)
+
+    User.get_by_username.return_value = None
+
+    admin.users_index(request)
+
+    User.get_by_email.assert_called_with("bob@builder.com")
+
 
 @users_index_fixtures
 def test_users_index_queries_annotation_count(User):
@@ -471,6 +483,7 @@ def test_users_index_no_user_found(User):
     request = DummyRequest(params={"username": "bob"},
                            es=es)
     User.get_by_username.return_value = None
+    User.get_by_email.return_value = None
 
     result = admin.users_index(request)