Use JavaScript in tests opening modal dialogs

This way we reproduce the user experience in the tests, and we can make
sure modal dialogs open when we expect it.

spec/system/admin/feature_flags_spec.rb

@@ -14,7 +14,7 @@ describe "Admin feature flags", :admin do
     end
   end
 
-  scenario "Disable a participatory process", :show_exceptions do
+  scenario "Disable a participatory process", :show_exceptions, :js do
     setting = Setting.find_by(key: "process.budgets")
     budget = create(:budget)
 
@@ -24,10 +24,11 @@ describe "Admin feature flags", :admin do
     within("#edit_setting_#{setting.id}") do
       expect(page).to have_button "Disable"
       expect(page).not_to have_button "Enable"
-      click_button "Disable"
+
+      accept_confirm { click_button "Disable" }
     end
 
-    visit admin_root_path
+    expect(page).to have_content "Value updated"
 
     within("#side_menu") do
       expect(page).not_to have_link "Participatory budgets"
@@ -43,7 +44,7 @@ describe "Admin feature flags", :admin do
     expect(page).to have_content "Internal server error"
   end
 
-  scenario "Enable a disabled participatory process" do
+  scenario "Enable a disabled participatory process", :js do
     Setting["process.budgets"] = nil
     setting = Setting.find_by(key: "process.budgets")
 
@@ -59,25 +60,28 @@ describe "Admin feature flags", :admin do
     within("#edit_setting_#{setting.id}") do
       expect(page).to have_button "Enable"
       expect(page).not_to have_button "Disable"
-      click_button "Enable"
+
+      accept_confirm { click_button "Enable" }
     end
 
-    visit admin_root_path
+    expect(page).to have_content "Value updated"
 
     within("#side_menu") do
       expect(page).to have_link "Participatory budgets"
     end
   end
 
-  scenario "Disable a feature" do
+  scenario "Disable a feature", :js do
     setting = Setting.find_by(key: "feature.twitter_login")
 
     visit admin_settings_path
+    click_link "Features"
 
     within("#edit_setting_#{setting.id}") do
       expect(page).to have_button "Disable"
       expect(page).not_to have_button "Enable"
-      click_button "Disable"
+
+      accept_confirm { click_button "Disable" }
     end
 
     expect(page).to have_content "Value updated"
@@ -88,15 +92,17 @@ describe "Admin feature flags", :admin do
     end
   end
 
-  scenario "Enable a disabled feature" do
+  scenario "Enable a disabled feature", :js do
     setting = Setting.find_by(key: "feature.map")
 
     visit admin_settings_path
+    click_link "Features"
 
     within("#edit_setting_#{setting.id}") do
       expect(page).to have_button "Enable"
       expect(page).not_to have_button "Disable"
-      click_button "Enable"
+
+      accept_confirm { click_button "Enable" }
     end
 
     expect(page).to have_content "Value updated"