move Request#download to Static plugin

#download() was a hangover from before the Static plugin existed and no longer worked. Also added missing specs so this won't happen again.

lib/express/plugins/static.js

@@ -111,6 +111,19 @@ exports.Static = Plugin.extend({
         sendfile: function(path) {
           (new exports.File(path)).sendTo(this)
           return this
+        },
+
+        /**
+         * Transfer static _file_ as an attachment.
+         * The basename of _file_ is used as the attachment filename.
+         *
+         * @param  {string} file
+         * @return {Request}
+         * @api public
+         */
+
+        download: function(file) {
+          return this.attachment(path.basename(file)).sendfile(file)
         }
       })
     }

lib/express/request.js

@@ -263,19 +263,6 @@ exports.Request = new Class({
     return this
   },
 
-  /**
-   * Transfer static file at the given _path_ as an attachment.
-   * The basename of _path_ is used as the attachment filename.
-   *
-   * @param  {string} path
-   * @return {Request}
-   * @api public
-   */
-
-  download: function(path) {
-    return this.attachment(basename(path)).sendfile(path)
-  },
-
   /**
    * Set Content-Disposition header to 'attachment',
    * with optional file _path_.

spec/spec.plugins.static.js

@@ -74,5 +74,31 @@ describe 'Express'
       end
     end
 
+    describe '#download()' 
+      describe 'when the file exists'
+        it 'should set attachment filename'
+          get('/report', function(){
+            this.download('report.pdf')
+            return 'foo'
+          })
+          get('/report').headers['content-disposition'].should.eql 'attachment; filename="report.pdf"'
+        end
+
+        it 'should transfer the file'
+          get('/public/*', function(file){
+            this.download('spec/fixtures/' + file)
+          })
+          get('/public/user.json').body.should.include '"name":'
+        end
+
+        it 'should automatically set the content type based on extension'
+          get('/public/*', function(file){
+            this.download('spec/fixtures/' + file)
+          })
+          get('/public/user.json').headers['content-type'].should.eql 'application/json'
+        end
+      end
+    end
+
   end
 end