Implement `modifier' run control keyword

spec/uh/wm/runner_spec.rb

@@ -21,10 +21,6 @@ module Uh
         expect(runner.events).to be_a Dispatcher
       end
 
-      it 'has a manager' do
-        expect(runner.manager).to be_a Manager
-      end
-
       it 'is not stopped' do
         expect(runner).not_to be_stopped
       end
@@ -53,6 +49,16 @@ module Uh
         end
       end
 
+      describe '#manager' do
+        it 'returns the manager' do
+          expect(runner.manager).to be_a Manager
+        end
+
+        it 'sets the manager modifier as env modifier' do
+          expect(runner.manager.modifier).to eq env.modifier
+        end
+      end
+
       describe '#evaluate_run_control' do
         it 'evaluates the run control file with RunControl and current env' do
           expect(RunControl).to receive(:evaluate).with env