respond to comments, add specs, make rubocop happy

Rakefile

@@ -6,7 +6,8 @@ require 'rspec/core/rake_task'
 RuboCop::RakeTask.new
 
 RSpec::Core::RakeTask.new
-
+LATEST_WEB_TGZ = 'http://dynamodb-local.s3-website-us-west-2.amazonaws.com'\
+                   '/dynamodb_local_latest.tar.gz'
 JAR_NAME = 'DynamoDBLocal.jar'
 LOCAL_JAR_DIR = '../lib/jars/dynamodb_local'
 SPEC_JAR_DIR = File.expand_path('./spec/dynamo-local-ruby/support/jars/')
@@ -30,9 +31,7 @@ task build: :download_dynamodb_local
 
 def download_jar(local_path)
   latest = File.join(local_path, 'dynamodb_local_latest.tar.gz')
-  latest_web_tgz = 'http://dynamodb-local.s3-website-us-west-2.amazonaws.com'\
-                   '/dynamodb_local_latest.tar.gz'
-  `wget #{latest_web_tgz} -O #{latest}` unless File.exist?(latest)
+  `wget #{LATEST_WEB_TGZ} -O #{latest}` unless File.exist?(latest)
   `tar xzf #{latest} -C #{local_path}`
   `rm #{latest}` if File.exist?(latest)
 end

lib/dynamo-local-ruby/dynamo_db_local.rb

@@ -44,11 +44,11 @@ def test_connection
         end
       end
 
-      private
       def teardown(pid)
         Process.kill('SIGINT', pid)
         Process.waitpid2(pid)
       rescue Errno::ESRCH
+        nil
       end
     end
 

spec/dynamo-local-ruby/dynamo_db_local_spec.rb

@@ -10,7 +10,21 @@
 
   describe '.up' do
     describe 'exit teardown' do
+      let(:pid) { 123 }
 
+      context 'pid exists' do
+        it 'kills and waits' do
+          Process.should_receive(:kill).with('SIGINT', pid)
+          Process.should_receive(:waitpid2).with(pid)
+          described_class.send(:teardown, pid)
+        end
+      end
+
+      context 'no pid' do
+        it 'does not raise' do
+          expect { described_class.send(:teardown, pid) }.not_to raise_error
+        end
+      end
     end
 
     after(:each) do