diff --git a/lib/jekyll/plugin_manager.rb b/lib/jekyll/plugin_manager.rb
index 45eeaa795..5acd0e46e 100644
--- a/lib/jekyll/plugin_manager.rb
+++ b/lib/jekyll/plugin_manager.rb
@@ -76,7 +76,7 @@ module Jekyll
     #
     # Returns an Array of plugin search paths
     def plugins_path
-      if site.config['plugins_dir'] == Jekyll::Configuration::DEFAULTS['plugins_dir']
+      if site.config['plugins_dir'].eql? Jekyll::Configuration::DEFAULTS['plugins_dir']
         [site.in_source_dir(site.config['plugins_dir'])]
       else
         Array(site.config['plugins_dir']).map { |d| File.expand_path(d) }
diff --git a/test/test_site.rb b/test/test_site.rb
index 89f646ed2..5e52a7c94 100644
--- a/test/test_site.rb
+++ b/test/test_site.rb
@@ -9,27 +9,27 @@ class TestSite < JekyllUnitTest
 
     should "look for plugins under the site directory by default" do
       site = Site.new(site_configuration)
-      assert_equal [File.join(source_dir, '_plugins')], site.plugins
+      assert_equal [source_dir('_plugins')], site.plugins
     end
 
     should "have an array for plugins if passed as a string" do
-      site = Site.new(build_configs({ 'plugins_dir' => '/tmp/plugins' }))
+      site = Site.new(site_configuration({ 'plugins_dir' => '/tmp/plugins' }))
       assert_equal ['/tmp/plugins'], site.plugins
     end
 
     should "have an array for plugins if passed as an array" do
-      site = Site.new(build_configs({ 'plugins_dir' => ['/tmp/plugins', '/tmp/otherplugins'] }))
+      site = Site.new(site_configuration({ 'plugins_dir' => ['/tmp/plugins', '/tmp/otherplugins'] }))
       assert_equal ['/tmp/plugins', '/tmp/otherplugins'], site.plugins
     end
 
     should "have an empty array for plugins if nothing is passed" do
-      site = Site.new(build_configs({ 'plugins_dir' => [] }))
+      site = Site.new(site_configuration({ 'plugins_dir' => [] }))
       assert_equal [], site.plugins
     end
 
-    should "have an empty array for plugins if nil is passed" do
-      site = Site.new(build_configs({ 'plugins_dir' => nil }))
-      assert_equal [], site.plugins
+    should "have the default for plugins if nil is passed" do
+      site = Site.new(site_configuration({ 'plugins_dir' => nil }))
+      assert_equal [source_dir('_plugins')], site.plugins
     end
 
     should "expose default baseurl" do
@@ -38,7 +38,7 @@ class TestSite < JekyllUnitTest
     end
 
     should "expose baseurl passed in from config" do
-      site = Site.new(build_configs({ 'baseurl' => '/blog' }))
+      site = Site.new(site_configuration({ 'baseurl' => '/blog' }))
       assert_equal '/blog', site.baseurl
     end
   end