Gracefully handle invalid states when filtering environments

Changelog: fixed

lib/api/environments.rb

@@ -30,6 +30,8 @@ class Environments < ::API::Base
         environments = ::Environments::EnvironmentsFinder.new(user_project, current_user, params).execute
         present paginate(environments), with: Entities::Environment, current_user: current_user
+      rescue ::Environments::EnvironmentsFinder::InvalidStatesError => exception
+        bad_request!(exception.message)
       end
       desc 'Creates a new environment' do

spec/requests/api/environments_spec.rb

@@ -151,6 +151,13 @@
           expect(json_response).to be_an Array
           expect(json_response.size).to eq(0)
         end
+
+        it 'returns a 400 status code with invalid states' do
+          get api("/projects/#{project.id}/environments?states=test", user)
+
+          expect(response).to have_gitlab_http_status(:bad_request)
+          expect(json_response['message']).to include('Requested states are invalid')
+        end
       end
     end