Add test code for 'whitelist' option.

features/site_configuration.feature

@@ -233,3 +233,26 @@ Feature: Site configuration
     Then the _site directory should exist
     And I should see "Whatever" in "_site/index.html"
     And I should see "this is a test" in "_site/test.txt"
+
+  Scenario: Add an empty whitelist to restrict all gems
+    Given I have an "index.html" file that contains "Whatever"
+    And I have a configuration file with:
+      | key       | value |
+      | gems      | [jekyll_test_plugin] |
+      | whitelist | [] |
+    When I run jekyll in safe mode
+    Then the _site directory should exist
+    And I should see "Whatever" in "_site/index.html"
+    And the "_site/test.txt" file should not exist
+
+  Scenario: Add a whitelist to restrict some gems but allow others
+    Given I have an "index.html" file that contains "Whatever"
+    And I have a configuration file with:
+      | key       | value |
+      | gems      | [jekyll_test_plugin, jekyll_test_plugin_malicious] |
+      | whitelist | [jekyll_test_plugin] |
+    When I run jekyll in safe mode
+    Then the _site directory should exist
+    And I should see "Whatever" in "_site/index.html"
+    And the "_site/test.txt" file should exist
+    And I should see "this is a test" in "_site/test.txt"

features/step_definitions/jekyll_steps.rb

@@ -126,6 +126,10 @@ When /^I run jekyll$/ do
   run_jekyll
 end
 
+When /^I run jekyll in safe mode$/ do
+  run_jekyll(:safe => true)
+end
+
 When /^I run jekyll with drafts$/ do
   run_jekyll(:drafts => true)
 end

features/support/env.rb

@@ -15,6 +15,7 @@ def run_jekyll(opts = {})
   command = JEKYLL_PATH.clone
   command << " build"
   command << " --drafts" if opts[:drafts]
+  command << " --safe" if opts[:safe]
   command << " >> /dev/null 2>&1" if opts[:debug].nil?
   system command
 end