1 files changed, 65 insertions, 0 deletions
diff --git a/spec/requests/api/graphql/mutations/merge_requests/reviewer_rereview_spec.rb b/spec/requests/api/graphql/mutations/merge_requests/reviewer_rereview_spec.rb
new file mode 100644
index 00000000000..2e4f35cbcde
--- /dev/null
+++ b/spec/requests/api/graphql/mutations/merge_requests/reviewer_rereview_spec.rb
@@ -0,0 +1,65 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'Setting assignees of a merge request' do
+  include GraphqlHelpers
+
+  let(:current_user) { create(:user) }
+  let(:merge_request) { create(:merge_request, reviewers: [user]) }
+  let(:project) { merge_request.project }
+  let(:user) { create(:user) }
+  let(:input) { { user_id: global_id_of(user) } }
+
+  let(:mutation) do
+    variables = {
+      project_path: project.full_path,
+      iid: merge_request.iid.to_s
+    }
+    graphql_mutation(:merge_request_reviewer_rereview, variables.merge(input),
+                     <<-QL.strip_heredoc
+                       clientMutationId
+                       errors
+    QL
+    )
+  end
+
+  def mutation_response
+    graphql_mutation_response(:merge_request_reviewer_rereview)
+  end
+
+  def mutation_errors
+    mutation_response['errors']
+  end
+
+  before do
+    project.add_developer(current_user)
+    project.add_developer(user)
+  end
+
+  it 'returns an error if the user is not allowed to update the merge request' do
+    post_graphql_mutation(mutation, current_user: create(:user))
+
+    expect(graphql_errors).not_to be_empty
+  end
+
+  describe 'reviewer does not exist' do
+    let(:input) { { user_id: global_id_of(create(:user)) } }
+
+    it 'returns an error' do
+      post_graphql_mutation(mutation, current_user: current_user)
+
+      expect(response).to have_gitlab_http_status(:success)
+      expect(mutation_errors).not_to be_empty
+    end
+  end
+
+  describe 'reviewer exists' do
+    it 'does not return an error' do
+      post_graphql_mutation(mutation, current_user: current_user)
+
+      expect(response).to have_gitlab_http_status(:success)
+      expect(mutation_errors).to be_empty
+    end
+  end
+end