Allow age to be altered in clean_assets rake task

CHANGELOG.md

@@ -4,6 +4,7 @@ Get upgrade notes from Sprockets 3.x to 4.x at https://github.com/rails/sprocket
 
 ## Master
 
+- Allow age to be altered in asset:clean rake task.
 - Fix `Sprockets::Server` to return lower-cased response headers to comply with Rack::Lint 3.0. [#744](https://github.com/rails/sprockets/pull/744)
 - Adding new directive `depend_on_directory` [#668](https://github.com/rails/sprockets/pull/668)
 - Fix `application/js-sourcemap+json` charset [#669](https://github.com/rails/sprockets/pull/669)

lib/rake/sprocketstask.rb

@@ -69,9 +69,12 @@ def manifest
     #
     attr_accessor :assets
 
-    # Number of old assets to keep.
+    # Minimum number of old assets to keep. See Sprockets::Manifest#clean for more information.
     attr_accessor :keep
 
+    # Assets created within this age will be kept. See Sprockets::Manifest#clean for more information.
+    attr_accessor :age
+
     # Logger to use during rake tasks. Defaults to using stderr.
     #
     #   t.logger = Logger.new($stdout)
@@ -103,6 +106,7 @@ def initialize(name = :assets)
       @logger       = Logger.new($stderr)
       @logger.level = Logger::INFO
       @keep         = 2
+      @age          = 3600
 
       yield self if block_given?
 
@@ -130,7 +134,7 @@ def define
       desc name == :assets ? "Clean old assets" : "Clean old #{name} assets"
       task "clean_#{name}" do
         with_logger do
-          manifest.clean(keep)
+          manifest.clean(keep, age)
         end
       end
 

test/test_rake_task.rb

@@ -61,6 +61,26 @@ def teardown
 
   end
 
+  test "clean" do
+    digest_path = @env['application.js'].digest_path
+    filename = fixture_path('default/application.coffee')
+
+    sandbox filename do
+      @rake[:assets].invoke
+      assert File.exist?("#{@dir}/#{digest_path}")
+
+      File.open(filename, 'w') { |f| f.write "change;" }
+      changed_digest_path = @env['application.js'].digest_path
+
+      @rake[:assets].invoke
+
+      @rake[:clean_assets].invoke(1, 0)
+
+      assert File.exist?("#{@dir}/#{digest_path}")
+      refute File.exist?("#{@dir}/#{changed_digest_path}")
+    end
+  end
+
   test "custom manifest directory" do
     Rake::SprocketsTask.new do |t|
       t.environment = nil