Filter issues by multiple assignee. Intargrate BE and FE parts

app/finders/issuable_finder.rb

@@ -26,7 +26,7 @@ class IssuableFinder
   IRRELEVANT_PARAMS_FOR_CACHE_KEY = %i[utf8 sort page state].freeze
 
   SCALAR_PARAMS = %i(scope state group_id project_id milestone_title assignee_id search label_name sort assignee_username author_id author_username authorized_only due_date iids non_archived weight).freeze
-  ARRAY_PARAMS = { label_name: [], iids: [] }.freeze
+  ARRAY_PARAMS = { label_name: [], iids: [], assignee_username: [] }.freeze
   VALID_PARAMS = (SCALAR_PARAMS + [ARRAY_PARAMS]).freeze
 
   attr_accessor :current_user, :params

app/finders/issues_finder.rb

@@ -118,8 +118,8 @@ class IssuesFinder < IssuableFinder
     @assignees =
       if params[:assignee_ids]
         User.where(id: params[:assignee_ids])
-      elsif params[:assignee_usernames]
-        User.where(username: params[:assignee_usernames])
+      elsif params[:assignee_username]
+        User.where(username: params[:assignee_username])
       else
         []
       end

spec/features/issues/filtered_search/filter_issues_spec.rb

@@ -196,7 +196,17 @@ describe 'Filter issues', js: true do
       end
 
       it 'filters issues by multiple assignees' do
-        skip('to be tested, issue #26546')
+        create(:issue, project: project, author: user, assignees: [user2, user])
+
+        input_filtered_search("assignee:@#{user.username} assignee:@#{user2.username}")
+
+        expect_tokens([
+          assignee_token(user.name),
+          assignee_token(user2.name)
+        ])
+
+        expect_issues_list_count(1)
+        expect_filtered_search_input_empty
       end
     end
 

spec/finders/issues_finder_spec.rb

@@ -64,7 +64,7 @@ describe IssuesFinder do
         let(:params) { { assignee_ids: [user2.id, user3.id] } }
 
         before do
-          project2.team << [user3, :developer]
+          project2.add_developer(user3)
 
           issue3.assignees = [user2, user3]
         end
@@ -76,10 +76,10 @@ describe IssuesFinder do
 
       context 'filtering by assignee usernames' do
         set(:user3) { create(:user) }
-        let(:params) { { assignee_usernames: [user2.username, user3.username] } }
+        let(:params) { { assignee_username: [user2.username, user3.username] } }
 
         before do
-          project2.team << [user3, :developer]
+          project2.add_developer(user3)
 
           issue3.assignees = [user2, user3]
         end