From 548c8c00a6656520b751f0c02c0a69cfb68912bd Mon Sep 17 00:00:00 2001
From: Thomas Walpole <twalpole@gmail.com>
Date: Mon, 10 Jul 2017 14:42:15 -0700
Subject: [PATCH] Add `ancestor` and `sibling` methods to node finders

---
 History.md                                 |  1 +
 lib/capybara.rb                            |  2 +
 lib/capybara/node/finders.rb               | 95 ++++++++++++++++++----
 lib/capybara/queries/ancestor_query.rb     | 25 ++++++
 lib/capybara/queries/sibling_query.rb      | 25 ++++++
 lib/capybara/spec/session/ancestor_spec.rb | 85 +++++++++++++++++++
 lib/capybara/spec/session/sibling_spec.rb  | 52 ++++++++++++
 lib/capybara/spec/views/with_html.erb      | 28 ++++++-
 8 files changed, 296 insertions(+), 17 deletions(-)
 create mode 100644 lib/capybara/queries/ancestor_query.rb
 create mode 100644 lib/capybara/queries/sibling_query.rb
 create mode 100644 lib/capybara/spec/session/ancestor_spec.rb
 create mode 100644 lib/capybara/spec/session/sibling_spec.rb

diff --git a/History.md b/History.md
index c1f59d20..d946324c 100644
--- a/History.md
+++ b/History.md
@@ -4,6 +4,7 @@ Release data: unreleased
 
 ### Added
 
+*  `sibling` and `ancestor` finders added [Thomas Walpole]
 *  Added built-in driver registrations `:selenium_chrome` and `:selenium_chrome_headless` [Thomas Walpole]
 *  Add `and_then` to Capybara RSpec matchers which behaves like the previous `and` compounder. [Thomas Walpole]
 *  Compound RSpec expectations with Capybara matchers now run both matchers inside a retry loop rather
diff --git a/lib/capybara.rb b/lib/capybara.rb
index 4ba32454..3e7bc80f 100644
--- a/lib/capybara.rb
+++ b/lib/capybara.rb
@@ -413,6 +413,8 @@ module Capybara
   require 'capybara/queries/title_query'
   require 'capybara/queries/current_path_query'
   require 'capybara/queries/match_query'
+  require 'capybara/queries/ancestor_query'
+  require 'capybara/queries/sibling_query'
   require 'capybara/query'
 
   require 'capybara/node/finders'
diff --git a/lib/capybara/node/finders.rb b/lib/capybara/node/finders.rb
index 5fdea240..c1db1776 100644
--- a/lib/capybara/node/finders.rb
+++ b/lib/capybara/node/finders.rb
@@ -34,22 +34,66 @@ module Capybara
         else
           args.push(session_options: session_options)
         end
-        query = Capybara::Queries::SelectorQuery.new(*args, &optional_filter_block)
-        synchronize(query.wait) do
-          if (query.match == :smart or query.match == :prefer_exact)
-            result = query.resolve_for(self, true)
-            result = query.resolve_for(self, false) if result.empty? && query.supports_exact? && !query.exact?
-          else
-            result = query.resolve_for(self)
-          end
-          if query.match == :one or query.match == :smart and result.size > 1
-            raise Capybara::Ambiguous.new("Ambiguous match, found #{result.size} elements matching #{query.description}")
-          end
-          if result.empty?
-            raise Capybara::ElementNotFound.new("Unable to find #{query.description}")
-          end
-          result.first
-        end.tap(&:allow_reload!)
+        synced_resolve Capybara::Queries::SelectorQuery.new(*args, &optional_filter_block)
+      end
+
+      ##
+      #
+      # Find an {Capybara::Node::Element} based on the given arguments that is also an ancestor of the element called on. +ancestor+ will raise an error if the element
+      # is not found.
+      #
+      # +ancestor+ takes the same options as +find+.
+      #
+      #     element.ancestor('#foo').find('.bar')
+      #     element.ancestor(:xpath, './/div[contains(., "bar")]')
+      #     element.ancestor('ul', text: 'Quox').click_link('Delete')
+      #
+      # @param (see Capybara::Node::Finders#find)
+      #
+      # @!macro waiting_behavior
+      #
+      # @option options [Boolean] match        The matching strategy to use.
+      #
+      # @return [Capybara::Node::Element]      The found element
+      # @raise  [Capybara::ElementNotFound]    If the element can't be found before time expires
+      #
+      def ancestor(*args, &optional_filter_block)
+        if args.last.is_a? Hash
+          args.last[:session_options] = session_options
+        else
+          args.push(session_options: session_options)
+        end
+        synced_resolve Capybara::Queries::AncestorQuery.new(*args, &optional_filter_block)
+      end
+
+      ##
+      #
+      # Find an {Capybara::Node::Element} based on the given arguments that is also a sibling of the element called on. +sibling+ will raise an error if the element
+      # is not found.
+      #
+      #
+      # +sibling+ takes the same options as +find+.
+      #
+      #     element.sibling('#foo').find('.bar')
+      #     element.sibling(:xpath, './/div[contains(., "bar")]')
+      #     element.sibling('ul', text: 'Quox').click_link('Delete')
+      #
+      # @param (see Capybara::Node::Finders#find)
+      #
+      # @macro waiting_behavior
+      #
+      # @option options [Boolean] match        The matching strategy to use.
+      #
+      # @return [Capybara::Node::Element]      The found element
+      # @raise  [Capybara::ElementNotFound]    If the element can't be found before time expires
+      #
+      def sibling(*args, &optional_filter_block)
+        if args.last.is_a? Hash
+          args.last[:session_options] = session_options
+        else
+          args.push(session_options: session_options)
+        end
+        synced_resolve Capybara::Queries::SiblingQuery.new(*args, &optional_filter_block)
       end
 
       ##
@@ -252,6 +296,25 @@ module Capybara
         nil
       end
 
+      private
+
+      def synced_resolve(query)
+        synchronize(query.wait) do
+          if (query.match == :smart or query.match == :prefer_exact)
+            result = query.resolve_for(self, true)
+            result = query.resolve_for(self, false) if result.empty? && query.supports_exact? && !query.exact?
+          else
+            result = query.resolve_for(self)
+          end
+          if query.match == :one or query.match == :smart and result.size > 1
+            raise Capybara::Ambiguous.new("Ambiguous match, found #{result.size} elements matching #{query.description}")
+          end
+          if result.empty?
+            raise Capybara::ElementNotFound.new("Unable to find #{query.description}")
+          end
+          result.first
+        end.tap(&:allow_reload!)
+      end
     end
   end
 end
diff --git a/lib/capybara/queries/ancestor_query.rb b/lib/capybara/queries/ancestor_query.rb
new file mode 100644
index 00000000..d618657f
--- /dev/null
+++ b/lib/capybara/queries/ancestor_query.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+module Capybara
+  module Queries
+    class AncestorQuery < MatchQuery
+      # @api private
+      def resolve_for(node, exact = nil)
+        @resolved_node = node
+        node.synchronize do
+          match_results = super(node.session.current_scope, exact)
+          node.all(:xpath, XPath.ancestor) do |el|
+            match_results.include?(el)
+          end
+        end
+      end
+
+      def description
+        desc = super
+        if @resolved_node && (child_query = @resolved_node.instance_variable_get(:@query))
+          desc += " that is an ancestor of #{child_query.description}"
+        end
+        desc
+      end
+    end
+  end
+end
diff --git a/lib/capybara/queries/sibling_query.rb b/lib/capybara/queries/sibling_query.rb
new file mode 100644
index 00000000..b0e183fc
--- /dev/null
+++ b/lib/capybara/queries/sibling_query.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+module Capybara
+  module Queries
+    class SiblingQuery < MatchQuery
+      # @api private
+      def resolve_for(node, exact = nil)
+        @resolved_node = node
+        node.synchronize do
+          match_results = super(node.session.current_scope, exact)
+          node.all(:xpath, XPath.preceding_sibling.union(XPath.following_sibling)) do |el|
+            match_results.include?(el)
+          end
+        end
+      end
+
+      def description
+        desc = super
+        if @resolved_node && (child_query = @resolved_node.instance_variable_get(:@query))
+          desc += " that is a sibling of #{child_query.description}"
+        end
+        desc
+      end
+    end
+  end
+end
diff --git a/lib/capybara/spec/session/ancestor_spec.rb b/lib/capybara/spec/session/ancestor_spec.rb
new file mode 100644
index 00000000..f3addf70
--- /dev/null
+++ b/lib/capybara/spec/session/ancestor_spec.rb
@@ -0,0 +1,85 @@
+# frozen_string_literal: true
+Capybara::SpecHelper.spec '#ancestor' do
+  before do
+    @session.visit('/with_html')
+  end
+
+  after do
+    Capybara::Selector.remove(:monkey)
+  end
+
+  it "should find the ancestor element using the given locator" do
+    el = @session.find(:css, '#first_image')
+    expect(el.ancestor('//p')).to have_text('Lorem ipsum dolor')
+    expect(el.ancestor("//a")[:'aria-label']).to eq('Go to simple')
+  end
+
+  it "should find the ancestor element using the given locator and options" do
+    el = @session.find(:css, '#child')
+    expect(el.ancestor('//div', text: 'Ancestor Ancestor Ancestor')[:id]).to eq('ancestor3')
+  end
+
+  it "should raise an error if there are multiple matches" do
+    el = @session.find(:css, '#child')
+    expect { el.ancestor('//div') }.to raise_error(Capybara::Ambiguous)
+    expect { el.ancestor('//div', text: 'Ancestor') }.to raise_error(Capybara::Ambiguous)
+  end
+
+  context "with css selectors" do
+    it "should find the first element using the given locator" do
+      el = @session.find(:css, '#first_image')
+      expect(el.ancestor(:css, 'p')).to have_text('Lorem ipsum dolor')
+      expect(el.ancestor(:css, 'a')[:'aria-label']).to eq('Go to simple')
+    end
+
+    it "should support pseudo selectors" do
+      el = @session.find(:css, '#button_img')
+      expect(el.ancestor(:css, 'button:disabled')[:id]).to eq('ancestor_button')
+    end
+  end
+
+  context "with xpath selectors" do
+    it "should find the first element using the given locator" do
+      el = @session.find(:css, '#first_image')
+      expect(el.ancestor(:xpath, '//p')).to have_text('Lorem ipsum dolor')
+      expect(el.ancestor(:xpath, "//a")[:'aria-label']).to eq('Go to simple')
+    end
+  end
+
+  context "with custom selector" do
+    it "should use the custom selector" do
+      Capybara.add_selector(:level) do
+        xpath { |num| ".//*[@id='ancestor#{num}']" }
+      end
+      el = @session.find(:css, '#child')
+      expect(el.ancestor(:level, 1).text).to eq('Ancestor Child')
+      expect(el.ancestor(:level, 3).text).to eq('Ancestor Ancestor Ancestor Child')
+    end
+  end
+
+
+  it "should raise ElementNotFound with a useful default message if nothing was found" do
+    el = @session.find(:css, '#child')
+    expect do
+      el.ancestor(:xpath, '//div[@id="nosuchthing"]')
+    end.to raise_error(Capybara::ElementNotFound, "Unable to find xpath \"//div[@id=\\\"nosuchthing\\\"]\" that is an ancestor of visible css \"#child\"")
+  end
+
+
+
+  context "within a scope" do
+    it "should limit the ancestors to inside the scope" do
+      @session.within(:css, '#ancestor2') do
+        el = @session.find(:css, '#child')
+        expect(el.ancestor(:css,'div', text: 'Ancestor')[:id]).to eq('ancestor1')
+      end
+    end
+  end
+
+  it "should raise if selector type is unknown" do
+    el = @session.find(:css, '#child')
+    expect do
+      el.ancestor(:unknown, '//h1')
+    end.to raise_error(ArgumentError)
+  end
+end
diff --git a/lib/capybara/spec/session/sibling_spec.rb b/lib/capybara/spec/session/sibling_spec.rb
new file mode 100644
index 00000000..893d9315
--- /dev/null
+++ b/lib/capybara/spec/session/sibling_spec.rb
@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+Capybara::SpecHelper.spec '#sibling' do
+  before do
+    @session.visit('/with_html')
+  end
+
+  after do
+    Capybara::Selector.remove(:monkey)
+  end
+
+  it "should find a prior sibling element using the given locator" do
+    el = @session.find(:css, '#mid_sibling')
+    expect(el.sibling('//div[@data-pre]')[:id]).to eq('pre_sibling')
+  end
+
+  it "should find a following sibling element using the given locator" do
+    el = @session.find(:css, '#mid_sibling')
+    expect(el.sibling('//div[@data-post]')[:id]).to eq('post_sibling')
+  end
+
+  it "should raise an error if there are multiple matches" do
+    el = @session.find(:css, '#mid_sibling')
+    expect { el.sibling('//div') }.to raise_error(Capybara::Ambiguous)
+  end
+
+  context "with css selectors" do
+    it "should find the first element using the given locator" do
+      el = @session.find(:css, '#mid_sibling')
+      expect(el.sibling(:css, '#pre_sibling')).to have_text('Pre Sibling')
+      expect(el.sibling(:css, '#post_sibling')).to have_text('Post Sibling')
+    end
+  end
+
+  context "with custom selector" do
+    it "should use the custom selector" do
+      Capybara.add_selector(:data_attribute) do
+        xpath { |attr| ".//*[@data-#{attr}]" }
+      end
+      el = @session.find(:css, '#mid_sibling')
+      expect(el.sibling(:data_attribute, 'pre').text).to eq('Pre Sibling')
+      expect(el.sibling(:data_attribute, 'post').text).to eq('Post Sibling')
+    end
+  end
+
+
+  it "should raise ElementNotFound with a useful default message if nothing was found" do
+    el = @session.find(:css, '#child')
+    expect do
+      el.sibling(:xpath, '//div[@id="nosuchthing"]')
+    end.to raise_error(Capybara::ElementNotFound, "Unable to find xpath \"//div[@id=\\\"nosuchthing\\\"]\" that is a sibling of visible css \"#child\"")
+  end
+end
diff --git a/lib/capybara/spec/views/with_html.erb b/lib/capybara/spec/views/with_html.erb
index 3f04a591..e8da0b3d 100644
--- a/lib/capybara/spec/views/with_html.erb
+++ b/lib/capybara/spec/views/with_html.erb
@@ -19,7 +19,7 @@
   et dolore magna aliqua. Ut enim ad minim veniam,
   quis nostrud exercitation <a href="/foo" id="foo">ullamco</a> laboris nisi
   ut aliquip ex ea commodo consequat.
-  <a href="/with_simple_html" aria-label="Go to simple"><img width="20" height="20" alt="awesome image" /></a>
+  <a href="/with_simple_html" aria-label="Go to simple"><img id="first_image" width="20" height="20" alt="awesome image" /></a>
 </p>
 
 <p class="para" id="second">
@@ -121,3 +121,29 @@ banana</textarea>
   <a id="link_placeholder">No href</a>
   <a id="link_blank_href" href="">Blank href</a>
 </div>
+
+<div id="ancestor3">
+  Ancestor
+  <div id="ancestor2">
+    Ancestor
+    <div id="ancestor1">
+      Ancestor
+      <div id="child">Child</div>
+    </div>
+  </div>
+  <button id="ancestor_button" type="submit" disabled>
+    <img id="button_img" width="20" height="20" alt="button img"/>
+  </button>
+</div>
+
+<div id="sibling_test">
+  <div id="sibling_wrapper" data-pre=true>
+    <div id="pre_sibling" data-pre=true>Pre Sibling</div>
+    <div id="mid_sibling">Mid Sibling</div>
+    <div id="post_sibling" data-post=true>Post Sibling</div>
+  </div>
+  <div id="other_sibling_wrapper" data-post=true>
+    <div data-pre=true>Pre Sibling</div>
+    <div data-post=true>Post Sibling</div>
+  </div>
+</div>
\ No newline at end of file