Add support for Node#obscured?

lib/capybara/cuprite/browser.rb

@@ -210,6 +210,10 @@ def path(node)
         evaluate_on(node: node, expression: "_cuprite.path(this)")
       end
 
+      def obscured?(node)
+        evaluate_on(node: node, expression: "_cuprite.isObscured(this)")
+      end
+
       def all_text(node)
         node.text
       end

lib/capybara/cuprite/javascripts/index.js

@@ -115,6 +115,35 @@ class Cuprite {
     return `//${selectors.join("/")}`;
   }
 
+  /**
+   * Returns true if the node is obscured in the viewport.
+   *
+   * @param {Element} node
+   * @return {boolean} true if the node is obscured, false otherwise
+   */
+  isObscured(node) {
+    let win = window;
+    let rect = node.getBoundingClientRect();
+    let px = rect.left + rect.width / 2;
+    let py = rect.top + rect.height / 2;
+
+    while (win) {
+      let topNode = win.document.elementFromPoint(px, py);
+
+      if (node !== topNode && !node.contains(topNode)) return true;
+
+      node = win.frameElement;
+      if (!node) return false;
+
+      rect = node.getBoundingClientRect();
+      px = rect.left + px;
+      py = rect.top + py;
+      win = win.parent;
+    }
+
+    return false;
+  }
+
   set(node, value) {
     if (node.readOnly) return;
 

lib/capybara/cuprite/node.rb

@@ -213,6 +213,10 @@ def path
         command(:path)
       end
 
+      def obscured?
+        command(:obscured?)
+      end
+
       def inspect
         %(#<#{self.class} @node=#{@node.inspect}>)
       end

spec/features/session_spec.rb

@@ -314,6 +314,31 @@
       end
     end
 
+    describe "Node#obscured?" do
+      context "when the element is not in the viewport of parent element" do
+        before do
+          @session.visit("/cuprite/scroll")
+        end
+
+        it "is is a boolean" do
+          expect(@session.find_link("Link outside viewport")).to be_obscured
+          expect(@session.find_link("Below the fold")).to be_obscured
+        end
+      end
+
+      context "when the element is only overlapped by descendants" do
+        before do
+          @session.visit("/with_html")
+        end
+
+        # copied from https://github.com/teamcapybara/capybara/blob/master/lib/capybara/spec/session/node_spec.rb#L328
+        # as this example is currently disabled on CI in the upstream suite
+        it "is not obscured" do
+          expect(@session.first(:css, "p:not(.para)")).not_to be_obscured
+        end
+      end
+    end
+
     it "has no trouble clicking elements when the size of a document changes" do
       @session.visit("/cuprite/long_page")
       @session.find(:css, "#penultimate").click

spec/spec_helper.rb

@@ -37,7 +37,6 @@ module TestSessions
 RSpec.configure do |config|
   config.define_derived_metadata do |metadata|
     regexes = <<~REGEXP.split("\n").map { |s| Regexp.quote(s.strip) }.join("|")
-      node #obscured?
       node #drag_to should work with jsTree
       node #drag_to should drag and drop an object
       node #drag_to should drag and drop if scrolling is needed
@@ -68,10 +67,6 @@ module TestSessions
       node #path reports when element in shadow dom
       node #shadow_root
       node #set should submit single text input forms if ended with
-      #all with obscured filter should only find nodes on top in the viewport when false
-      #all with obscured filter should not find nodes on top outside the viewport when false
-      #all with obscured filter should find top nodes outside the viewport when true
-      #all with obscured filter should only find non-top nodes when true
       #fill_in should fill in a color field
       #fill_in should handle carriage returns with line feeds in a textarea correctly
       #has_field with valid should be false if field is invalid