Use mute gem for capturing stdout

hi.gemspec

@@ -24,6 +24,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'cane',           '~> 2.6.1'
   spec.add_development_dependency 'cane-hashcheck', '~> 1.2.0'
   spec.add_development_dependency 'coveralls',      '~> 0.7.0'
+  spec.add_development_dependency 'mute',           '~> 1.0.0'
   spec.add_development_dependency 'pry',            '~> 0.9.12.4'
   spec.add_development_dependency 'rack-test',      '~> 0.6.2'
   spec.add_development_dependency 'rake',           '~> 10.1.1'

spec/hi/logger_spec.rb

@@ -11,7 +11,7 @@
     end
 
     it 'prints message to standard out' do
-      stdout = capture_stdout do
+      stdout = Mute::IO.capture_stdout do
         logger.log message
       end
 
@@ -25,24 +25,11 @@
     end
 
     it 'does not print message to standard out' do
-      stdout = capture_stdout do
+      stdout = Mute::IO.capture_stdout do
         logger.log message
       end
 
       expect(stdout).to be_empty
     end
   end
-
-  private
-
-  def capture_stdout
-    captured = StringIO.new
-    stdout = $stdout
-    $stdout = captured
-
-    yield
-
-    $stdout = stdout
-    captured.string
-  end
 end

spec/spec_helper.rb

@@ -1,4 +1,5 @@
 require 'pry'
+require 'mute'
 require 'coveralls'
 Coveralls.wear!