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/shared/system/documentable.rb

@@ -95,37 +95,37 @@ shared_examples "documentable" do |documentable_factory_name, documentable_path,
   end
 
   context "Destroy" do
-    scenario "Should show success notice after successful document upload" do
+    scenario "Should show success notice after successful document upload", :js do
       login_as documentable.author
 
       visit send(documentable_path, arguments)
 
       within "#document_#{document.id}" do
-        click_on "Delete document"
+        accept_confirm { click_link "Delete document" }
       end
 
       expect(page).to have_content "Document was deleted successfully."
     end
 
-    scenario "Should hide documents tab if there is no documents" do
+    scenario "Should hide documents tab if there is no documents", :js do
       login_as documentable.author
 
       visit send(documentable_path, arguments)
 
       within "#document_#{document.id}" do
-        click_on "Delete document"
+        accept_confirm { click_link "Delete document" }
       end
 
       expect(page).not_to have_content "Documents (0)"
     end
 
-    scenario "Should redirect to documentable path after successful deletion" do
+    scenario "Should redirect to documentable path after successful deletion", :js do
       login_as documentable.author
 
       visit send(documentable_path, arguments)
 
       within "#document_#{document.id}" do
-        click_on "Delete document"
+        accept_confirm { click_link "Delete document" }
       end
 
       within "##{ActionView::RecordIdentifier.dom_id(documentable)}" do