Improve rescript tests

In this commit, a deply is put between UI interaction and database
check. This, fixed false positive test pass for not updating database on
empty form submission.

spec/rescript/rescript_spec.rb

@@ -50,26 +50,35 @@
       fill_in author_field, with: comment.author
       fill_in text_field, with: comment.text
       click_button("Post")
+
+      page.driver.browser.manage.timeouts.implicit_wait = 1
+
       expect(Comment.all.count).to equal(new_comment_count)
     end
 
     it "comment count remains the same when author field is empty" do
       initial_comment_count = Comment.all.count
       fill_in text_field, with: comment.text
       click_button("Post")
+
+      expect(page).to have_text(/Can't save the comment!/)
       expect(Comment.all.count).to equal(initial_comment_count)
     end
 
     it "comment count remains the same when text field is empty" do
       initial_comment_count = Comment.all.count
       fill_in author_field, with: comment.author
       click_button("Post")
+
+      expect(page).to have_text(/Can't save the comment!/)
       expect(Comment.all.count).to equal(initial_comment_count)
     end
 
     it "comment count remains the same when both form fields are empty" do
       initial_comment_count = Comment.all.count
       click_button("Post")
+
+      expect(page).to have_text(/Can't save the comment!/)
       expect(Comment.all.count).to equal(initial_comment_count)
     end
   end