diff --git a/app/models/issue.rb b/app/models/issue.rb
index 582caaa60..fa4545180 100644
--- a/app/models/issue.rb
+++ b/app/models/issue.rb
@@ -1089,7 +1089,7 @@ class Issue < ActiveRecord::Base
     if user.logged?
       s << ' created-by-me' if author_id == user.id
       s << ' assigned-to-me' if assigned_to_id == user.id
-      s << ' assigned-to-my-group' if user.groups.any? {|g| g.id = assigned_to_id}
+      s << ' assigned-to-my-group' if user.groups.any? {|g| g.id == assigned_to_id}
     end
     s
   end
diff --git a/test/unit/issue_test.rb b/test/unit/issue_test.rb
index 8b0252e0b..d53d551fd 100644
--- a/test/unit/issue_test.rb
+++ b/test/unit/issue_test.rb
@@ -2202,16 +2202,19 @@ class IssueTest < ActiveSupport::TestCase
     assert_include 'priority-highest', classes
   end
 
-  def test_css_classes_should_include_user_assignment
-    issue = Issue.generate(:assigned_to_id => 2)
-    assert_include 'assigned-to-me', issue.css_classes(User.find(2))
-    assert_not_include 'assigned-to-me', issue.css_classes(User.find(3))
-  end
-
-  def test_css_classes_should_include_user_group_assignment
-    issue = Issue.generate(:assigned_to_id => 10)
-    assert_include 'assigned-to-my-group', issue.css_classes(Group.find(10).users.first)
-    assert_not_include 'assigned-to-my-group', issue.css_classes(User.find(3))
+  def test_css_classes_should_include_user_and_group_assignment
+    project = Project.first
+    user = User.generate!
+    group = Group.generate!
+    Member.create!(:principal => group, :project => project, :role_ids => [1, 2])
+    group.users << user
+    assert user.member_of?(project)
+    issue1 = Issue.generate(:assigned_to_id => group.id)
+    assert_include 'assigned-to-my-group', issue1.css_classes(user)
+    assert_not_include 'assigned-to-me', issue1.css_classes(user)
+    issue2 = Issue.generate(:assigned_to_id => user.id)
+    assert_not_include 'assigned-to-my-group', issue2.css_classes(user)
+    assert_include 'assigned-to-me', issue2.css_classes(user)
   end
 
   def test_save_attachments_with_hash_should_save_attachments_in_keys_order