Fix RoutingError when changing username to non ascii char.

app/controllers/admin/users_controller.rb

@@ -84,6 +84,8 @@ class Admin::UsersController < Admin::ApplicationController
         format.html { redirect_to [:admin, admin_user], notice: 'User was successfully updated.' }
         format.json { head :ok }
       else
+        # restore username to keep form action url.
+        admin_user.username = params[:id]
         format.html { render action: "edit" }
         format.json { render json: admin_user.errors, status: :unprocessable_entity }
       end

features/admin/users.feature

@@ -6,3 +6,11 @@ Feature: Admin Users
   Scenario: On Admin Users
     Given I visit admin users page
     Then I should see all users
+
+  Scenario: Edit user and change username to non ascii char
+    When I visit admin users page
+    And Click edit
+    And Input non ascii char in username
+    And Click save
+    Then See username error message
+    And Not chenged form action url

features/steps/admin/admin_users.rb

@@ -8,4 +8,27 @@ class AdminUsers < Spinach::FeatureSteps
       page.should have_content user.name
     end
   end
+
+  And 'Click edit' do
+    @user = User.first
+    find("#edit_user_#{@user.id}").click
+  end
+
+  And 'Input non ascii char in username' do
+    fill_in 'user_username', with: "\u3042\u3044"
+  end
+
+  And 'Click save' do
+    click_button("Save")
+  end
+
+  Then 'See username error message' do
+    within "#error_explanation" do
+      page.should have_content "Username"
+    end
+  end
+
+  And 'Not chenged form action url' do
+    page.should have_selector %(form[action="/admin/users/#{@user.username}"])
+  end
 end