Add specs to test on_stop and action on environments

lib/gitlab/ci/config/node/environment.rb

@@ -64,6 +64,10 @@ module Gitlab
             value[:action] || 'start'
           end
 
+          def on_stop
+            value[:on_stop]
+          end
+
           def value
             case @config
             when String then { name: @config, action: 'start' }

spec/lib/gitlab/ci/config/node/environment_spec.rb

@@ -101,7 +101,7 @@ describe Gitlab::Ci::Config::Node::Environment do
   context 'when invalid action is used' do
     let(:config) do
       { name: 'production',
-        action: false }
+        action: 'invalid' }
     end
 
     describe '#valid?' do
@@ -144,7 +144,7 @@ describe Gitlab::Ci::Config::Node::Environment do
     describe '#errors' do
       it 'contains error about invalid action' do
         expect(entry.errors)
-          .to include 'environment action should be start or stop'
+          .to include 'environment on stop should be a string'
       end
     end
   end