Add params validations and remove extra params support

Remove label_name and milestone_title params support
Add mutually_exclusive validation for author_id and author_username
Add mutually_exclusive validation for assignee_id and assignee_username
Add validation to allow single value for asignee_username on CE
Add separate issue_stats_params helper for statistics params and
reuse in issues_params.

1 files changed, 24 insertions, 2 deletions

diff --git a/spec/requests/api/issues/get_project_issues_spec.rb b/spec/requests/api/issues/get_project_issues_spec.rb
index afd5bd2257f..a07d7673345 100644
--- a/spec/requests/api/issues/get_project_issues_spec.rb
+++ b/spec/requests/api/issues/get_project_issues_spec.rb
@@ -490,11 +490,33 @@ describe API::Issues do
       let!(:issue2) { create(:issue, author: user2, project: project, created_at: 2.days.ago) }
       let!(:issue3) { create(:issue, author: user2, assignees: [assignee, another_assignee], project: project, created_at: 1.day.ago) }
 
-      it 'returns issues with multiple assignees' do
-        get api("#{base_url}/issues", user), params: { assignee_username: [assignee.username, another_assignee.username] }
+      it 'returns issues by assignee_username' do
+        get api("/issues", user), params: { assignee_username: [assignee.username], scope: 'all' }
 
+        expect(issue3.reload.assignees.pluck(:id)).to match_array([assignee.id, another_assignee.id])
         expect_paginated_array_response([confidential_issue.id, issue3.id])
       end
+
+      it 'returns issues by assignee_username as string' do
+        get api("/issues", user), params: { assignee_username: assignee.username, scope: 'all' }
+
+        expect(issue3.reload.assignees.pluck(:id)).to match_array([assignee.id, another_assignee.id])
+        expect_paginated_array_response([confidential_issue.id, issue3.id])
+      end
+
+      it 'returns error when multiple assignees are passed' do
+        get api("/issues", user), params: { assignee_username: [assignee.username, another_assignee.username], scope: 'all' }
+
+        expect(response).to have_gitlab_http_status(400)
+        expect(json_response["error"]).to include("allows one value, but found 2")
+      end
+
+      it 'returns error when assignee_username and assignee_id are passed together' do
+        get api("/issues", user), params: { assignee_username: [assignee.username], assignee_id: another_assignee.id, scope: 'all' }
+
+        expect(response).to have_gitlab_http_status(400)
+        expect(json_response["error"]).to include("mutually exclusive")
+      end
     end
   end