diff --git a/spec/features/fluentd/setting/source_and_output_spec.rb b/spec/features/fluentd/setting/source_and_output_spec.rb
index aba8121..9f45ce1 100644
--- a/spec/features/fluentd/setting/source_and_output_spec.rb
+++ b/spec/features/fluentd/setting/source_and_output_spec.rb
@@ -89,4 +89,60 @@ describe "source_and_output", js: true do
       end
     end
   end
+
+  describe "edit, update, delete" do
+    let(:config_contents) { <<-CONF.strip_heredoc }
+      <source>
+        type forward
+        port 24224
+      </source>
+    CONF
+    let(:new_config) { <<-CONF.strip_heredoc }
+      <source>
+        type http
+        port 8899
+      </source>
+    CONF
+
+    before do
+      all(".input .panel .panel-heading").first.click
+    end
+
+    it "click edit button transform textarea, then click cancel button to be reset" do
+      page.should_not have_css('.input textarea')
+      find(".btn", text: I18n.t('terms.edit')).click
+      page.should have_css('.input textarea')
+      find('.input textarea').value.should == config_contents
+      find('.input textarea').set "foo"
+      find(".btn", text: I18n.t('terms.cancel')).click
+      content = wait_until do
+        page.evaluate_script("document.querySelector('.input pre').textContent")
+      end
+      content.should == config_contents
+      daemon.agent.config.strip.should == config_contents.strip
+    end
+
+    it "click edit button transform textarea, then click update button to be stored" do
+      page.should_not have_css('.input textarea')
+      find(".btn", text: I18n.t('terms.edit')).click
+      page.should have_css('.input textarea')
+      find('.input textarea').value.should == config_contents
+      find('.input textarea').set new_config
+      find(".btn", text: I18n.t('terms.update')).click
+      content = wait_until do
+        page.evaluate_script("document.querySelector('.input pre').textContent")
+      end
+      content.should == new_config
+      daemon.agent.config.strip.should == new_config.strip
+    end
+
+    it "click delete button transform textarea" do
+      page.should have_css('.input .panel-body')
+      page.execute_script "__backup = window.confirm; window.confirm = function(){return true;}"
+      find(".btn", text: I18n.t('terms.destroy')).click
+      page.should_not have_css('.input .panel-body')
+      page.execute_script "window.confirm = __backup;"
+      daemon.agent.config.strip.should == ""
+    end
+  end
 end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 603e70f..21554b3 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -34,6 +34,18 @@ RSpec.configure do |config|
   # Syntax sugar to use the FactoryGirl methods directly instead FactoryGirl.create ete.
   config.include FactoryGirl::Syntax::Methods
   config.include LoginMacro
+  def wait_until(seconds = 5, &block)
+    timeout(seconds) do
+      loop do
+        begin
+          ret = block.call
+          break ret if ret
+        rescue Capybara::Poltergeist::JavascriptError
+        end
+        sleep 0.01
+      end
+    end
+  end
 
   # If true, the base class of anonymous controllers will be inferred
   # automatically. This will be the default behavior in future versions of