Print a warning when in dry run mode

spec/producer/core/env_spec.rb

@@ -113,8 +113,8 @@ module Producer::Core
         expect(output.string).to include 'some message'
       end
 
-      it 'has a log level of ERROR' do
-        expect(env.logger.level).to eq Logger::ERROR
+      it 'has a log level of WARN' do
+        expect(env.logger.level).to eq Logger::WARN
       end
 
       it 'uses our formatter' do
@@ -135,6 +135,13 @@ module Producer::Core
         expect(env.logger).to receive(:info).with 'message'
         env.log 'message'
       end
+
+      context 'when second argument is :warn' do
+        it 'logs a warning message through the assigned logger' do
+          expect(env.logger).to receive(:warn).with 'message'
+          env.log 'message', :warn
+        end
+      end
     end
 
     describe '#verbose?' do

spec/producer/core/logger_formatter_spec.rb

@@ -13,6 +13,14 @@ module Producer::Core
       it 'returns the given message with a line separator' do
         expect(subject).to eq "#{message}\n"
       end
+
+      context 'when severity is WARN' do
+        let(:severity) { 'WARN' }
+
+        it 'prefix the message with `Warning:\'' do
+          expect(subject).to match /\AWarning: #{message}/
+        end
+      end
     end
   end
 end

spec/producer/core/worker_spec.rb

@@ -10,6 +10,18 @@ module Producer::Core
         expect(worker).to receive(:process_task).with(:some_task)
         worker.process [:some_task]
       end
+
+      context 'when dry run is enabled' do
+        before { allow(env).to receive(:dry_run?) { true } }
+
+        it 'warns dry run is enabled' do
+          expect(env).to receive(:log).with(
+            /\Arunning in dry run mode, actions will NOT be applied\z/,
+            :warn
+          )
+          worker.process []
+        end
+      end
     end
 
     describe '#process_task' do