Use have_link to check for links in tests

Using `have_selector` Capybara might detect `<a>` tags which are not
links because they don't have an `href` attribute. Besides, with
`have_selector` Capybara only detects visible text, which means it won't
detect links which are icons with tooltips.

spec/system/admin/poll/questions_spec.rb

@@ -15,30 +15,30 @@ describe "Admin poll questions", :admin do
 
     within("#poll_question_#{question1.id}") do
       expect(page).to have_content(question1.title)
-      expect(page).to have_content("Edit answers")
-      expect(page).to have_content("Edit")
-      expect(page).to have_content("Delete")
+      expect(page).to have_link "Edit answers"
+      expect(page).to have_link "Edit"
+      expect(page).to have_link "Delete"
     end
 
     visit admin_poll_path(poll2)
     expect(page).to have_content(poll2.name)
 
     within("#poll_question_#{question2.id}") do
-      expect(page).to have_content(question2.title)
-      expect(page).to have_content("Edit answers")
-      expect(page).to have_content("Edit")
-      expect(page).to have_content("Delete")
+      expect(page).to have_content question2.title
+      expect(page).to have_link "Edit answers"
+      expect(page).to have_link "Edit"
+      expect(page).to have_link "Delete"
     end
 
     visit admin_poll_path(poll3)
     expect(page).to have_content(poll3.name)
 
     within("#poll_question_#{question3.id}") do
-      expect(page).to have_content(question3.title)
-      expect(page).to have_link("(See proposal)", href: proposal_path(question3.proposal))
-      expect(page).to have_content("Edit answers")
-      expect(page).to have_content("Edit")
-      expect(page).to have_content("Delete")
+      expect(page).to have_content question3.title
+      expect(page).to have_link "(See proposal)", href: proposal_path(question3.proposal)
+      expect(page).to have_link "Edit answers"
+      expect(page).to have_link "Edit"
+      expect(page).to have_link "Delete"
     end
   end