1 files changed, 54 insertions, 0 deletions
diff --git a/spec/support/helpers/merge_request_diff_helpers.rb b/spec/support/helpers/merge_request_diff_helpers.rb
index 30afde7efed..7515c789add 100644
--- a/spec/support/helpers/merge_request_diff_helpers.rb
+++ b/spec/support/helpers/merge_request_diff_helpers.rb
@@ -1,8 +1,11 @@
 # frozen_string_literal: true
 
 module MergeRequestDiffHelpers
+  PageEndReached = Class.new(StandardError)
+
   def click_diff_line(line_holder, diff_side = nil)
     line = get_line_components(line_holder, diff_side)
+    scroll_to_elements_bottom(line_holder)
     line_holder.hover
     line[:num].find('.js-add-diff-note-button').click
   end
@@ -27,4 +30,55 @@ module MergeRequestDiffHelpers
     line_holder.find('.diff-line-num', match: :first)
     { content: line_holder.all('.line_content')[side_index], num: line_holder.all('.diff-line-num')[side_index] }
   end
+
+  def has_reached_page_end
+    evaluate_script("(window.innerHeight + window.scrollY) >= document.body.offsetHeight")
+  end
+
+  def scroll_to_elements_bottom(element)
+    evaluate_script("(function(el) {
+      window.scrollBy(0, el.getBoundingClientRect().bottom - window.innerHeight);
+    })(arguments[0]);", element.native)
+  end
+
+  # we're not using Capybara's .obscured here because it also checks if the element is clickable
+  def within_viewport?(element)
+    evaluate_script("(function(el) {
+      var rect = el.getBoundingClientRect();
+      return (
+        rect.bottom >= 0 &&
+        rect.right >= 0 &&
+        rect.top <= (window.innerHeight || document.documentElement.clientHeight) &&
+        rect.left <= (window.innerWidth || document.documentElement.clientWidth)
+      );
+    })(arguments[0]);", element.native)
+  end
+
+  def find_within_viewport(selector, **options)
+    begin
+      element = find(selector, **options, wait: 2)
+    rescue Capybara::ElementNotFound
+      return
+    end
+    return element if within_viewport?(element)
+
+    nil
+  end
+
+  def find_by_scrolling(selector, **options)
+    element = find_within_viewport(selector, **options)
+    return element if element
+
+    page.execute_script "window.scrollTo(0,0)"
+    until element
+
+      if has_reached_page_end
+        raise PageEndReached, "Failed to find any elements matching a selector '#{selector}' by scrolling. Page end reached."
+      end
+
+      page.execute_script "window.scrollBy(0,window.innerHeight/1.5)"
+      element = find_within_viewport(selector, **options)
+    end
+    element
+  end
 end