[Multiple issue assignees] specs fix

spec/controllers/projects/boards/issues_controller_spec.rb

@@ -34,7 +34,7 @@ describe Projects::Boards::IssuesController do
           issue = create(:labeled_issue, project: project, labels: [planning])
           create(:labeled_issue, project: project, labels: [planning])
           create(:labeled_issue, project: project, labels: [development], due_date: Date.tomorrow)
-          create(:labeled_issue, project: project, labels: [development], assignee: johndoe)
+          create(:labeled_issue, project: project, labels: [development], assignees: [johndoe])
           issue.subscribe(johndoe, project)
 
           list_issues user: user, board: board, list: list2

spec/controllers/projects/issues_controller_spec.rb

@@ -336,7 +336,7 @@ describe Projects::IssuesController do
     let(:admin) { create(:admin) }
     let!(:issue) { create(:issue, project: project) }
     let!(:unescaped_parameter_value) { create(:issue, :confidential, project: project, author: author) }
-    let!(:request_forgery_timing_attack) { create(:issue, :confidential, project: project, assignee: assignee) }
+    let!(:request_forgery_timing_attack) { create(:issue, :confidential, project: project, assignees: [assignee]) }
 
     describe 'GET #index' do
       it 'does not list confidential issues for guests' do

spec/controllers/projects/merge_requests_controller_spec.rb

@@ -1329,7 +1329,7 @@ describe Projects::MergeRequestsController do
     end
 
     it 'correctly pluralizes flash message on success' do
-      issue2.update!(assignee: user)
+      issue2.update!(assignees: [user])
 
       post_assign_issues
 

spec/features/atom/dashboard_issues_spec.rb

@@ -32,7 +32,7 @@ describe "Dashboard Issues Feed", feature: true  do
       end
 
       context "issue with basic fields" do
-        let!(:issue2) { create(:issue, author: user, assignee: assignee, project: project2, description: 'test desc') }
+        let!(:issue2) { create(:issue, author: user, assignees: [assignee], project: project2, description: 'test desc') }
 
         it "renders issue fields" do
           visit issues_dashboard_path(:atom, private_token: user.private_token)
@@ -51,7 +51,7 @@ describe "Dashboard Issues Feed", feature: true  do
       context "issue with label and milestone" do
         let!(:milestone1) { create(:milestone, project: project1, title: 'v1') }
         let!(:label1)     { create(:label, project: project1, title: 'label1') }
-        let!(:issue1)     { create(:issue, author: user, assignee: assignee, project: project1, milestone: milestone1) }
+        let!(:issue1)     { create(:issue, author: user, assignees: [assignee], project: project1, milestone: milestone1) }
 
         before do
           issue1.labels << label1

spec/features/atom/issues_spec.rb

@@ -6,7 +6,7 @@ describe 'Issues Feed', feature: true  do
     let!(:assignee) { create(:user, email: 'private2@example.com', public_email: 'public2@example.com') }
     let!(:group)    { create(:group) }
     let!(:project)  { create(:project) }
-    let!(:issue)    { create(:issue, author: user, assignee: assignee, project: project) }
+    let!(:issue)    { create(:issue, author: user, assignees: [assignee], project: project) }
 
     before do
       project.team << [user, :developer]

spec/features/boards/modal_filter_spec.rb

@@ -98,7 +98,7 @@ describe 'Issue Boards add issue modal filtering', :feature, :js do
   end
 
   context 'assignee' do
-    let!(:issue) { create(:issue, project: project, assignee: user2) }
+    let!(:issue) { create(:issue, project: project, assignees: [user2]) }
 
     before do
       project.team << [user2, :developer]

spec/features/boards/sidebar_spec.rb

@@ -11,7 +11,7 @@ describe 'Issue Boards', feature: true, js: true do
   let!(:bug)         { create(:label, project: project, name: 'Bug') }
   let!(:regression)  { create(:label, project: project, name: 'Regression') }
   let!(:stretch)     { create(:label, project: project, name: 'Stretch') }
-  let!(:issue1)      { create(:labeled_issue, project: project, assignee: user, milestone: milestone, labels: [development], relative_position: 2) }
+  let!(:issue1)      { create(:labeled_issue, project: project, assignees: [user], milestone: milestone, labels: [development], relative_position: 2) }
   let!(:issue2)      { create(:labeled_issue, project: project, labels: [development, stretch], relative_position: 1) }
   let(:board)        { create(:board, project: project) }
   let!(:list)        { create(:list, board: board, label: development, position: 0) }

spec/features/dashboard/issuables_counter_spec.rb

@@ -7,7 +7,7 @@ describe 'Navigation bar counter', feature: true, js: true, caching: true do
   let(:merge_request) { create(:merge_request, source_project: project) }
 
   before do
-    issue.update(assignee: user)
+    issue.assignees = [user]
     merge_request.update(assignee: user)
     login_as(user)
   end
@@ -17,7 +17,7 @@ describe 'Navigation bar counter', feature: true, js: true, caching: true do
 
     expect_counters('issues', '1')
 
-    issue.update(assignee: nil)
+    issue.assignees = []
     visit issues_dashboard_path
 
     expect_counters('issues', '1')

spec/features/dashboard/issues_spec.rb

@@ -11,7 +11,7 @@ RSpec.describe 'Dashboard Issues', feature: true do
 
   let!(:authored_issue) { create :issue, author: current_user, project: project }
   let!(:authored_issue_on_public_project) { create :issue, author: current_user, project: public_project }
-  let!(:assigned_issue) { create :issue, assignee: current_user, project: project }
+  let!(:assigned_issue) { create :issue, assignees: [current_user], project: project }
   let!(:other_issue) { create :issue, project: project }
 
   before do

spec/features/dashboard_issues_spec.rb

@@ -10,8 +10,8 @@ describe "Dashboard Issues filtering", feature: true, js: true do
       project.team << [user, :master]
       login_as(user)
 
-      create(:issue, project: project, author: user, assignee: user)
-      create(:issue, project: project, author: user, assignee: user, milestone: milestone)
+      create(:issue, project: project, author: user, assignees: [user])
+      create(:issue, project: project, author: user, assignees: [user], milestone: milestone)
 
       visit_issues
     end

spec/features/gitlab_flavored_markdown_spec.rb

@@ -52,11 +52,11 @@ describe "GitLab Flavored Markdown", feature: true do
     before do
       @other_issue = create(:issue,
                             author: @user,
-                            assignee: @user,
+                            assignees: [@user],
                             project: project)
       @issue = create(:issue,
                       author: @user,
-                      assignee: @user,
+                      assignees: [@user],
                       project: project,
                       title: "fix #{@other_issue.to_reference}",
                       description: "ask #{fred.to_reference} for details")

spec/features/issues/award_emoji_spec.rb

@@ -7,7 +7,7 @@ describe 'Awards Emoji', feature: true do
   let!(:user)      { create(:user) }
   let(:issue) do
     create(:issue,
-           assignee: @user,
+           assignees: [@user],
            project: project)
   end
 

spec/features/issues/filtered_search/filter_issues_weight_spec.rb

@@ -31,7 +31,7 @@ describe 'Filter issues weight', js: true, feature: true do
       title: 'Bug report 1',
       milestone: milestone,
       author: user,
-      assignee: user)
+      assignees: [user])
     issue.labels << label
 
     visit namespace_project_issues_path(project.namespace, project)

spec/features/issues/form_spec.rb

@@ -9,7 +9,7 @@ describe 'New/edit issue', feature: true, js: true do
   let!(:milestone) { create(:milestone, project: project) }
   let!(:label)     { create(:label, project: project) }
   let!(:label2)    { create(:label, project: project) }
-  let!(:issue)     { create(:issue, project: project, assignee: user, milestone: milestone) }
+  let!(:issue)     { create(:issue, project: project, assignees: [user], milestone: milestone) }
 
   before do
     project.team << [user, :master]

spec/features/issues/update_issues_spec.rb

@@ -101,7 +101,7 @@ feature 'Multiple issue updating from issues#index', feature: true do
   end
 
   def create_assigned
-    create(:issue, project: project, assignee: user)
+    create(:issue, project: project, assignees: [user])
   end
 
   def create_with_milestone

spec/features/issues_spec.rb

@@ -19,7 +19,7 @@ describe 'Issues', feature: true do
     let!(:issue) do
       create(:issue,
              author: @user,
-             assignee: @user,
+             assignees: [@user],
              project: project)
     end
 
@@ -44,7 +44,7 @@ describe 'Issues', feature: true do
     let!(:issue) do
       create(:issue,
              author: @user,
-             assignee: @user,
+             assignees: [@user],
              project: project)
     end
 
@@ -139,7 +139,7 @@ describe 'Issues', feature: true do
 
   describe 'Issue info' do
     it 'excludes award_emoji from comment count' do
-      issue = create(:issue, author: @user, assignee: @user, project: project, title: 'foobar')
+      issue = create(:issue, author: @user, assignees: [@user], project: project, title: 'foobar')
       create(:award_emoji, awardable: issue)
 
       visit namespace_project_issues_path(project.namespace, project, assignee_id: @user.id)
@@ -165,14 +165,14 @@ describe 'Issues', feature: true do
       %w(foobar barbaz gitlab).each do |title|
         create(:issue,
                author: @user,
-               assignee: @user,
+               assignees: [@user],
                project: project,
                title: title)
       end
 
       @issue = Issue.find_by(title: 'foobar')
       @issue.milestone = create(:milestone, project: project)
-      @issue.assignee = nil
+      @issue.assignees = []
       @issue.save
     end
 
@@ -408,7 +408,7 @@ describe 'Issues', feature: true do
   end
 
   describe 'update labels from issue#show', js: true do
-    let(:issue) { create(:issue, project: project, author: @user, assignee: @user) }
+    let(:issue) { create(:issue, project: project, author: @user, assignees: [@user]) }
     let!(:label) { create(:label, project: project) }
 
     before do
@@ -426,7 +426,7 @@ describe 'Issues', feature: true do
   end
 
   describe 'update assignee from issue#show' do
-    let(:issue) { create(:issue, project: project, author: @user, assignee: @user) }
+    let(:issue) { create(:issue, project: project, author: @user, assignees: [@user]) }
 
     context 'by authorized user' do
       it 'allows user to select unassigned', js: true do
@@ -668,7 +668,7 @@ describe 'Issues', feature: true do
 
   describe 'due date' do
     context 'update due on issue#show', js: true do
-      let(:issue) { create(:issue, project: project, author: @user, assignee: @user) }
+      let(:issue) { create(:issue, project: project, author: @user, assignees: [@user]) }
 
       before do
         visit namespace_project_issue_path(project.namespace, project, issue)

spec/features/milestones/show_spec.rb

@@ -5,10 +5,10 @@ describe 'Milestone show', feature: true do
   let(:project) { create(:empty_project) }
   let(:milestone) { create(:milestone, project: project) }
   let(:labels) { create_list(:label, 2, project: project) }
-  let(:issue_params) { { project: project, assignee: user, author: user, milestone: milestone, labels: labels } }
+  let(:issue_params) { { project: project, assignees: [user], author: user, milestone: milestone, labels: labels } }
 
   before do
-    project.add_user(user, :developer) 
+    project.add_user(user, :developer)
     login_as(user)
   end
 

spec/features/projects/issuable_templates_spec.rb

@@ -14,7 +14,7 @@ feature 'issuable templates', feature: true, js: true do
   context 'user creates an issue using templates' do
     let(:template_content) { 'this is a test "bug" template' }
     let(:longtemplate_content) { %Q(this\n\n\n\n\nis\n\n\n\n\na\n\n\n\n\nbug\n\n\n\n\ntemplate) }
-    let(:issue) { create(:issue, author: user, assignee: user, project: project) }
+    let(:issue) { create(:issue, author: user, assignees: [user], project: project) }
     let(:description_addition) { ' appending to description' }
 
     background do
@@ -74,7 +74,7 @@ feature 'issuable templates', feature: true, js: true do
   context 'user creates an issue using templates, with a prior description' do
     let(:prior_description) { 'test issue description' }
     let(:template_content) { 'this is a test "bug" template' }
-    let(:issue) { create(:issue, author: user, assignee: user, project: project) }
+    let(:issue) { create(:issue, author: user, assignees: [user], project: project) }
 
     background do
       project.repository.create_file(

spec/features/search_spec.rb

@@ -6,7 +6,7 @@ describe "Search", feature: true  do
 
   let(:user) { create(:user) }
   let(:project) { create(:project, namespace: user.namespace) }
-  let!(:issue) { create(:issue, project: project, assignee: user) }
+  let!(:issue) { create(:issue, project: project, assignees: [user]) }
   let!(:issue2) { create(:issue, project: project, author: user) }
 
   before do

spec/finders/issues_finder_spec.rb

@@ -7,12 +7,12 @@ describe IssuesFinder do
   let(:project2) { create(:empty_project) }
   let(:milestone) { create(:milestone, project: project1) }
   let(:label) { create(:label, project: project2) }
-  let(:issue1) { create(:issue, author: user, assignee: user, project: project1, milestone: milestone, title: 'gitlab') }
-  let(:issue2) { create(:issue, author: user, assignee: user, project: project2, description: 'gitlab') }
-  let(:issue3) { create(:issue, author: user2, assignee: user2, project: project2) }
+  let(:issue1) { create(:issue, author: user, assignees: [user], project: project1, milestone: milestone, title: 'gitlab') }
+  let(:issue2) { create(:issue, author: user, assignees: [user], project: project2, description: 'gitlab') }
+  let(:issue3) { create(:issue, author: user2, assignees: [user2], project: project2) }
 
   describe '#execute' do
-    let(:closed_issue) { create(:issue, author: user2, assignee: user2, project: project2, state: 'closed') }
+    let(:closed_issue) { create(:issue, author: user2, assignees: [user2], project: project2, state: 'closed') }
     let!(:label_link) { create(:label_link, label: label, target: issue2) }
     let(:search_user) { user }
     let(:params) { {} }
@@ -107,7 +107,7 @@ describe IssuesFinder do
 
         before do
           milestones.each do |milestone|
-            create(:issue, project: milestone.project, milestone: milestone, author: user, assignee: user)
+            create(:issue, project: milestone.project, milestone: milestone, author: user, assignees: [user])
           end
         end
 
@@ -142,7 +142,7 @@ describe IssuesFinder do
 
         before do
           milestones.each do |milestone|
-            create(:issue, project: milestone.project, milestone: milestone, author: user, assignee: user)
+            create(:issue, project: milestone.project, milestone: milestone, author: user, assignees: [user])
           end
         end
 

spec/lib/gitlab/elastic/project_search_results_spec.rb

@@ -100,7 +100,7 @@ describe Gitlab::Elastic::ProjectSearchResults, lib: true do
     let(:admin) { create(:admin) }
     let!(:issue) { create(:issue, project: project, title: 'Issue 1') }
     let!(:security_issue_1) { create(:issue, :confidential, project: project, title: 'Security issue 1', author: author) }
-    let!(:security_issue_2) { create(:issue, :confidential, title: 'Security issue 2', project: project, assignee: assignee) }
+    let!(:security_issue_2) { create(:issue, :confidential, title: 'Security issue 2', project: project, assignees: [assignee]) }
 
     before do
       Gitlab::Elastic::Helper.refresh_index

spec/lib/gitlab/elastic/search_results_spec.rb

@@ -89,9 +89,9 @@ describe Gitlab::Elastic::SearchResults, lib: true do
     before do
       @issue = create(:issue, project: project_1, title: 'Issue 1', iid: 1)
       @security_issue_1 = create(:issue, :confidential, project: project_1, title: 'Security issue 1', author: author, iid: 2)
-      @security_issue_2 = create(:issue, :confidential, title: 'Security issue 2', project: project_1, assignee: assignee, iid: 3)
+      @security_issue_2 = create(:issue, :confidential, title: 'Security issue 2', project: project_1, assignees: [assignee], iid: 3)
       @security_issue_3 = create(:issue, :confidential, project: project_2, title: 'Security issue 3', author: author, iid: 1)
-      @security_issue_4 = create(:issue, :confidential, project: project_3, title: 'Security issue 4', assignee: assignee, iid: 1)
+      @security_issue_4 = create(:issue, :confidential, project: project_3, title: 'Security issue 4', assignees: [assignee], iid: 1)
       @security_issue_5 = create(:issue, :confidential, project: project_4, title: 'Security issue 5', iid: 1)
 
       Gitlab::Elastic::Helper.refresh_index

spec/lib/gitlab/import_export/project_tree_saver_spec.rb

@@ -189,7 +189,7 @@ describe Gitlab::ImportExport::ProjectTreeSaver, services: true do
   end
 
   def setup_project
-    issue = create(:issue, assignee: user)
+    issue = create(:issue, assignees: [user])
     snippet = create(:project_snippet)
     release = create(:release)
     group = create(:group)

spec/lib/gitlab/project_search_results_spec.rb

@@ -86,7 +86,7 @@ describe Gitlab::ProjectSearchResults, lib: true do
     let(:project) { create(:empty_project, :internal) }
     let!(:issue) { create(:issue, project: project, title: 'Issue 1') }
     let!(:security_issue_1) { create(:issue, :confidential, project: project, title: 'Security issue 1', author: author) }
-    let!(:security_issue_2) { create(:issue, :confidential, title: 'Security issue 2', project: project, assignee: assignee) }
+    let!(:security_issue_2) { create(:issue, :confidential, title: 'Security issue 2', project: project, assignees: [assignee]) }
 
     it 'does not list project confidential issues for non project members' do
       results = described_class.new(non_member, project, query)

spec/lib/gitlab/search_results_spec.rb

@@ -72,9 +72,9 @@ describe Gitlab::SearchResults do
     let(:admin) { create(:admin) }
     let!(:issue) { create(:issue, project: project_1, title: 'Issue 1') }
     let!(:security_issue_1) { create(:issue, :confidential, project: project_1, title: 'Security issue 1', author: author) }
-    let!(:security_issue_2) { create(:issue, :confidential, title: 'Security issue 2', project: project_1, assignee: assignee) }
+    let!(:security_issue_2) { create(:issue, :confidential, title: 'Security issue 2', project: project_1, assignees: [assignee]) }
     let!(:security_issue_3) { create(:issue, :confidential, project: project_2, title: 'Security issue 3', author: author) }
-    let!(:security_issue_4) { create(:issue, :confidential, project: project_3, title: 'Security issue 4', assignee: assignee) }
+    let!(:security_issue_4) { create(:issue, :confidential, project: project_3, title: 'Security issue 4', assignees: [assignee]) }
     let!(:security_issue_5) { create(:issue, :confidential, project: project_4, title: 'Security issue 5') }
 
     it 'does not list confidential issues for non project members' do

spec/models/concerns/issuable_spec.rb

@@ -57,21 +57,6 @@ describe Issue, "Issuable" do
     end
   end
 
-  describe 'assignee_name' do
-    it 'is delegated to assignee' do
-      issue.update!(assignee: create(:user))
-
-      expect(issue.assignee_name).to eq issue.assignee.name
-    end
-
-    it 'returns nil when assignee is nil' do
-      issue.assignee_id = nil
-      issue.save(validate: false)
-
-      expect(issue.assignee_name).to eq nil
-    end
-  end
-
   describe "before_save" do
     describe "#update_cache_counts" do
       context "when previous assignee exists" do

spec/models/concerns/milestoneish_spec.rb

@@ -11,13 +11,13 @@ describe Milestone, 'Milestoneish' do
   let(:milestone) { create(:milestone, project: project) }
   let!(:issue) { create(:issue, project: project, milestone: milestone) }
   let!(:security_issue_1) { create(:issue, :confidential, project: project, author: author, milestone: milestone) }
-  let!(:security_issue_2) { create(:issue, :confidential, project: project, assignee: assignee, milestone: milestone) }
+  let!(:security_issue_2) { create(:issue, :confidential, project: project, assignees: [assignee], milestone: milestone) }
   let!(:closed_issue_1) { create(:issue, :closed, project: project, milestone: milestone) }
   let!(:closed_issue_2) { create(:issue, :closed, project: project, milestone: milestone) }
   let!(:closed_security_issue_1) { create(:issue, :confidential, :closed, project: project, author: author, milestone: milestone) }
-  let!(:closed_security_issue_2) { create(:issue, :confidential, :closed, project: project, assignee: assignee, milestone: milestone) }
+  let!(:closed_security_issue_2) { create(:issue, :confidential, :closed, project: project, assignees: [assignee], milestone: milestone) }
   let!(:closed_security_issue_3) { create(:issue, :confidential, :closed, project: project, author: author, milestone: milestone) }
-  let!(:closed_security_issue_4) { create(:issue, :confidential, :closed, project: project, assignee: assignee, milestone: milestone) }
+  let!(:closed_security_issue_4) { create(:issue, :confidential, :closed, project: project, assignees: [assignee], milestone: milestone) }
   let!(:merge_request) { create(:merge_request, source_project: project, target_project: project, milestone: milestone) }
 
   before do

spec/models/event_spec.rb

@@ -92,8 +92,8 @@ describe Event, models: true do
     let(:author) { create(:author) }
     let(:assignee) { create(:user) }
     let(:admin) { create(:admin) }
-    let(:issue) { create(:issue, project: project, author: author, assignee: assignee) }
-    let(:confidential_issue) { create(:issue, :confidential, project: project, author: author, assignee: assignee) }
+    let(:issue) { create(:issue, project: project, author: author, assignees: [assignee]) }
+    let(:confidential_issue) { create(:issue, :confidential, project: project, author: author, assignees: [assignee]) }
     let(:note_on_commit) { create(:note_on_commit, project: project) }
     let(:note_on_issue) { create(:note_on_issue, noteable: issue, project: project) }
     let(:note_on_confidential_issue) { create(:note_on_issue, noteable: confidential_issue, project: project) }

spec/models/issue_spec.rb

@@ -166,7 +166,7 @@ describe Issue, models: true do
   describe '#is_being_reassigned?' do
     it 'returns issues assigned to user' do
       user = create(:user)
-      create_list(:issue, 2, assignee: user)
+      create_list(:issue, 2, assignees: [user])
 
       expect(Issue.open_for(user).count).to eq 2
     end
@@ -399,7 +399,7 @@ describe Issue, models: true do
     it 'updates when assignees change' do
       user1 = create(:user)
       user2 = create(:user)
-      issue = create(:issue, assignee: user1)
+      issue = create(:issue, assignees: [user1])
 
       expect(user1.assigned_open_issues_count).to eq(1)
       expect(user2.assigned_open_issues_count).to eq(0)

spec/policies/issues_policy_spec.rb

@@ -15,7 +15,7 @@ describe IssuePolicy, models: true do
   context 'a private project' do
     let(:non_member) { create(:user) }
     let(:project) { create(:empty_project, :private) }
-    let(:issue) { create(:issue, project: project, assignee: assignee, author: author) }
+    let(:issue) { create(:issue, project: project, assignees: [assignee], author: author) }
     let(:issue_no_assignee) { create(:issue, project: project) }
 
     before do
@@ -69,7 +69,7 @@ describe IssuePolicy, models: true do
     end
 
     context 'with confidential issues' do
-      let(:confidential_issue) { create(:issue, :confidential, project: project, assignee: assignee, author: author) }
+      let(:confidential_issue) { create(:issue, :confidential, project: project, assignees: [assignee], author: author) }
       let(:confidential_issue_no_assignee) { create(:issue, :confidential, project: project) }
 
       it 'does not allow non-members to read confidential issues' do
@@ -110,7 +110,7 @@ describe IssuePolicy, models: true do
 
   context 'a public project' do
     let(:project) { create(:empty_project, :public) }
-    let(:issue) { create(:issue, project: project, assignee: assignee, author: author) }
+    let(:issue) { create(:issue, project: project, assignees: [assignee], author: author) }
     let(:issue_no_assignee) { create(:issue, project: project) }
 
     before do
@@ -157,7 +157,7 @@ describe IssuePolicy, models: true do
     end
 
     context 'with confidential issues' do
-      let(:confidential_issue) { create(:issue, :confidential, project: project, assignee: assignee, author: author) }
+      let(:confidential_issue) { create(:issue, :confidential, project: project, assignees: [assignee], author: author) }
       let(:confidential_issue_no_assignee) { create(:issue, :confidential, project: project) }
 
       it 'does not allow guests to read confidential issues' do

spec/requests/api/issues_spec.rb

@@ -15,7 +15,7 @@ describe API::Issues, api: true  do
   let!(:closed_issue) do
     create :closed_issue,
            author: user,
-           assignee: user,
+           assignees: [user],
            project: project,
            state: :closed,
            milestone: milestone,
@@ -27,14 +27,14 @@ describe API::Issues, api: true  do
            :confidential,
            project: project,
            author: author,
-           assignee: assignee,
+           assignees: [assignee],
            created_at: generate(:issue_created_at),
            updated_at: 2.hours.ago
   end
   let!(:issue) do
     create :issue,
            author: user,
-           assignee: user,
+           assignees: [user],
            project: project,
            milestone: milestone,
            created_at: generate(:issue_created_at),
@@ -296,7 +296,7 @@ describe API::Issues, api: true  do
     let!(:group_closed_issue) do
       create :closed_issue,
              author: user,
-             assignee: user,
+             assignees: [user],
              project: group_project,
              state: :closed,
              milestone: group_milestone,
@@ -307,13 +307,13 @@ describe API::Issues, api: true  do
              :confidential,
              project: group_project,
              author: author,
-             assignee: assignee,
+             assignees: [assignee],
              updated_at: 2.hours.ago
     end
     let!(:group_issue) do
       create :issue,
              author: user,
-             assignee: user,
+             assignees: [user],
              project: group_project,
              milestone: group_milestone,
              updated_at: 1.hour.ago

spec/requests/api/v3/issues_spec.rb

@@ -15,7 +15,7 @@ describe API::V3::Issues, api: true  do
   let!(:closed_issue) do
     create :closed_issue,
            author: user,
-           assignee: user,
+           assignees: [user],
            project: project,
            state: :closed,
            milestone: milestone,
@@ -27,14 +27,14 @@ describe API::V3::Issues, api: true  do
            :confidential,
            project: project,
            author: author,
-           assignee: assignee,
+           assignees: [assignee],
            created_at: generate(:issue_created_at),
            updated_at: 2.hours.ago
   end
   let!(:issue) do
     create :issue,
            author: user,
-           assignee: user,
+           assignees: [user],
            project: project,
            milestone: milestone,
            created_at: generate(:issue_created_at),
@@ -248,7 +248,7 @@ describe API::V3::Issues, api: true  do
     let!(:group_closed_issue) do
       create :closed_issue,
              author: user,
-             assignee: user,
+             assignees: [user],
              project: group_project,
              state: :closed,
              milestone: group_milestone,
@@ -259,13 +259,13 @@ describe API::V3::Issues, api: true  do
              :confidential,
              project: group_project,
              author: author,
-             assignee: assignee,
+             assignees: [assignee],
              updated_at: 2.hours.ago
     end
     let!(:group_issue) do
       create :issue,
              author: user,
-             assignee: user,
+             assignees: [user],
              project: group_project,
              milestone: group_milestone,
              updated_at: 1.hour.ago

spec/services/issues/close_service_spec.rb

@@ -4,7 +4,7 @@ describe Issues::CloseService, services: true do
   let(:user) { create(:user) }
   let(:user2) { create(:user) }
   let(:guest) { create(:user) }
-  let(:issue) { create(:issue, assignee: user2) }
+  let(:issue) { create(:issue, assignees: [user2]) }
   let(:project) { issue.project }
   let!(:todo) { create(:todo, :assigned, user: user, project: project, target: issue, author: user2) }
 

spec/services/issues/update_service_spec.rb

@@ -196,7 +196,7 @@ describe Issues::UpdateService, services: true do
 
       context 'when is reassigned' do
         before do
-          update_issue(assignee: user2)
+          update_issue(assignees: [user2])
         end
 
         it 'marks previous assignee todos as done' do

spec/services/merge_requests/assign_issues_service_spec.rb

@@ -16,7 +16,7 @@ describe MergeRequests::AssignIssuesService, services: true do
   end
 
   it 'ignores issues already assigned to any user' do
-    issue.update!(assignee: create(:user))
+    issue.assignees = [create(:user)]
 
     expect(service.assignable_issues).to be_empty
   end
@@ -44,7 +44,7 @@ describe MergeRequests::AssignIssuesService, services: true do
   end
 
   it 'assigns these to the merge request owner' do
-    expect { service.execute }.to change { issue.reload.assignee }.to(user)
+    expect { service.execute }.to change { issue.assignees.first }.to(user)
   end
 
   it 'ignores external issues' do

spec/services/projects/autocomplete_service_spec.rb

@@ -11,7 +11,7 @@ describe Projects::AutocompleteService, services: true do
       let(:project) { create(:empty_project, :public) }
       let!(:issue) { create(:issue, project: project, title: 'Issue 1') }
       let!(:security_issue_1) { create(:issue, :confidential, project: project, title: 'Security issue 1', author: author) }
-      let!(:security_issue_2) { create(:issue, :confidential, title: 'Security issue 2', project: project, assignee: assignee) }
+      let!(:security_issue_2) { create(:issue, :confidential, title: 'Security issue 2', project: project, assignees: [assignee]) }
 
       it 'does not list project confidential issues for guests' do
         autocomplete = described_class.new(project, nil)

spec/services/todo_service_spec.rb

@@ -22,11 +22,11 @@ describe TodoService, services: true do
   end
 
   describe 'Issues' do
-    let(:issue) { create(:issue, project: project, assignee: john_doe, author: author, description: "- [ ] Task 1\n- [ ] Task 2 #{mentions}") }
-    let(:addressed_issue) { create(:issue, project: project, assignee: john_doe, author: author, description: "#{directly_addressed}\n- [ ] Task 1\n- [ ] Task 2") }
-    let(:unassigned_issue) { create(:issue, project: project, assignee: nil) }
-    let(:confidential_issue) { create(:issue, :confidential, project: project, author: author, assignee: assignee, description: mentions) }
-    let(:addressed_confident_issue) { create(:issue, :confidential, project: project, author: author, assignee: assignee, description: directly_addressed) }
+    let(:issue) { create(:issue, project: project, assignees: [john_doe], author: author, description: "- [ ] Task 1\n- [ ] Task 2 #{mentions}") }
+    let(:addressed_issue) { create(:issue, project: project, assignees: [john_doe], author: author, description: "#{directly_addressed}\n- [ ] Task 1\n- [ ] Task 2") }
+    let(:unassigned_issue) { create(:issue, project: project, assignees: []) }
+    let(:confidential_issue) { create(:issue, :confidential, project: project, author: author, assignees: [assignee], description: mentions) }
+    let(:addressed_confident_issue) { create(:issue, :confidential, project: project, author: author, assignees: [assignee], description: directly_addressed) }
 
     describe '#new_issue' do
       it 'creates a todo if assigned' do
@@ -40,7 +40,7 @@ describe TodoService, services: true do
       end
 
       it 'creates a todo if assignee is the current user' do
-        unassigned_issue.update_attribute(:assignee, john_doe)
+        unassigned_issue.assignees = [john_doe]
         service.new_issue(unassigned_issue, john_doe)
 
         should_create_todo(user: john_doe, target: unassigned_issue, author: john_doe, action: Todo::ASSIGNED)
@@ -343,7 +343,7 @@ describe TodoService, services: true do
     describe '#new_note' do
       let!(:first_todo) { create(:todo, :assigned, user: john_doe, project: project, target: issue, author: author) }
       let!(:second_todo) { create(:todo, :assigned, user: john_doe, project: project, target: issue, author: author) }
-      let(:confidential_issue) { create(:issue, :confidential, project: project, author: author, assignee: assignee) }
+      let(:confidential_issue) { create(:issue, :confidential, project: project, author: author, assignees: [assignee]) }
       let(:note) { create(:note, project: project, noteable: issue, author: john_doe, note: mentions) }
       let(:addressed_note) { create(:note, project: project, noteable: issue, author: john_doe, note: directly_addressed) }
       let(:note_on_commit) { create(:note_on_commit, project: project, author: john_doe, note: mentions) }
@@ -783,7 +783,7 @@ describe TodoService, services: true do
   end
 
   it 'updates cached counts when a todo is created' do
-    issue = create(:issue, project: project, assignee: john_doe, author: author, description: mentions)
+    issue = create(:issue, project: project, assignees: [john_doe], author: author, description: mentions)
 
     expect(john_doe.todos_pending_count).to eq(0)
     expect(john_doe).to receive(:update_todos_count_cache).and_call_original
@@ -795,8 +795,8 @@ describe TodoService, services: true do
   end
 
   describe '#mark_todos_as_done' do
-    let(:issue) { create(:issue, project: project, author: author, assignee: john_doe) }
-    let(:another_issue) { create(:issue, project: project, author: author, assignee: john_doe) }
+    let(:issue) { create(:issue, project: project, author: author, assignees: [john_doe]) }
+    let(:another_issue) { create(:issue, project: project, author: author, assignees: [john_doe]) }
 
     it 'marks a relation of todos as done' do
       create(:todo, :mentioned, user: john_doe, target: issue, project: project)

spec/support/import_export/export_file_helper.rb

@@ -10,7 +10,7 @@ module ExportFileHelper
 
     create(:release, project: project)
 
-    issue = create(:issue, assignee: user, project: project)
+    issue = create(:issue, assignees: [user], project: project)
     snippet = create(:project_snippet, project: project)
     label = create(:label, project: project)
     milestone = create(:milestone, project: project)