diff --git a/lib/pagy/extras/standalone.rb b/lib/pagy/extras/standalone.rb
index b6a99a5fe..2233978f2 100644
--- a/lib/pagy/extras/standalone.rb
+++ b/lib/pagy/extras/standalone.rb
@@ -46,7 +46,11 @@ def pagy_url_for(pagy, page, deprecated_url=nil, absolute: nil)
       "#{url_string}#{query_string}#{p_vars[:fragment]}"
     end
   end
-  Helpers.prepend UseStandaloneExtra
+
+  #  single line in order to avoid complicating simplecov already tested with other GitHub Actions
+  Gem::Version.new(RUBY_VERSION) >= Gem::Version.new('3.0.0') \
+      && Helpers.prepend(UseStandaloneExtra) \
+      || ( Frontend.prepend(UseStandaloneExtra); Backend.prepend(UseStandaloneExtra) if defined?(Pagy::Backend::METADATA) ) # rubocop:disable Style/Semicolon
 
   # defines a dummy #params method if not already defined in the including module
   module Backend
diff --git a/pagy-on-docker/docker-compose-backport.yml b/pagy-on-docker/docker-compose-backport.yml
new file mode 100644
index 000000000..09cb955e8
--- /dev/null
+++ b/pagy-on-docker/docker-compose-backport.yml
@@ -0,0 +1,103 @@
+# Basic pagy-on-docker development environment
+# it will keep the installed gems and HOME in the pagy_bundle and pagy_user_home pagy-on-docker volumes
+# the pagy-jekill service will be updating a live preview for the docs
+
+# USAGE
+#   cd pagy-on-docker
+#   docker-compose up pagy           # only pagy service (running ruby development and test environment)
+#   docker-compose up pagy-jekyll    # pagy and pagy-jekyll services (add the docs live site)
+#   docker-compose up pagy-cyress    # pagy and pagy-cyress services (run the e2e tests and exit)
+
+version: "3.8"
+
+services:
+
+  # ruby dev and test pagy development
+  # It also runs a minimal sinatra app at http://0.0.0.0:8080
+  pagy:
+    image: pagy:4-backport
+    build:
+      context: .
+      dockerfile: pagy-backport.dockerfile
+      # set env variables with your user info
+      args:
+        user: $USER
+        group: $GROUP
+        uid: $UID
+        gid: $GID
+        password: "${PASSWORD:-rubydev}"
+        term: ${TERM:-xterm-256color}
+    container_name: pagy
+    volumes:
+      - ../.:/opt/project
+      - bundle:/usr/local/bundle
+      - user_home:/home/$USER
+    environment:
+      - COVERAGE_REPORT
+    stdin_open: true
+    tty: true
+
+  # Serve the docs site live at http://0.0.0.0:4000
+  # Use it to check/edit the rendered content in the docs dir
+  pagy-jekyll:
+    depends_on:
+      - pagy
+    image: pagy-jekyll:latest
+    build:
+      context: .
+      dockerfile: pagy-jekyll.dockerfile
+    container_name: pagy-jekyll
+    environment:
+      - JEKYLL_GITHUB_TOKEN
+    ports:
+      - "4000:4000"
+      - "35729:35729"
+    volumes:
+      - ../docs:/opt/docs
+      - docs_site:/opt/site
+    command: |
+      jekyll serve \
+          --incremental \
+          --livereload \
+          --watch \
+          --force-polling \
+          --host 0.0.0.0 \
+          --baseurl '' \
+          --source /opt/docs \
+          --destination /opt/site
+    stdin_open: true
+    tty: true
+
+  # you may want skip this service when you run the docker-compose.yml file
+  # and run it only on demand to run the tests and exit, or to interact with cypress
+  # using the additional open-cypress.yml (see the comments in the open-cypress.yml file)
+  # IMPORTANT: pick the build.dockerfile entry according to your UID
+  pagy-cypress:
+    depends_on:
+      - pagy
+    image: pagy-cypress:latest
+    build:
+      context: .
+      # switch between the following 2 lines if your user id is 1000 or not
+      dockerfile: pagy-cypress-uid1000.dockerfile
+      # dockerfile: pagy-cypress.dockerfile
+      args:
+        user: $USER
+        group: $GROUP
+        uid: $UID
+        gid: $GID
+    container_name: pagy-cypress
+    environment:
+      - CYPRESS_baseUrl=http://pagy:4567
+    working_dir: /test/e2e
+    volumes:
+      - ../test/e2e:/test/e2e
+
+volumes:
+  bundle:
+    name: pagy_backport_bundle
+  user_home:
+    name: pagy_backport_user_home
+  docs_site:
+    name: pagy_docs_site
+
diff --git a/pagy-on-docker/pagy-backport.dockerfile b/pagy-on-docker/pagy-backport.dockerfile
new file mode 100644
index 000000000..0a82548b0
--- /dev/null
+++ b/pagy-on-docker/pagy-backport.dockerfile
@@ -0,0 +1,55 @@
+FROM ruby:2.7
+
+ARG term
+ENV TERM="${term:-xterm-256color}"
+
+# install required packages
+RUN apt-get update && apt-get install -y locales \
+ && sed -i 's/^# *\(en_US.UTF-8\)/\1/' /etc/locale.gen \
+ && locale-gen \
+ && apt-get install -y \
+        nodejs \
+        git \
+        nano
+
+ARG user
+ARG group
+ARG uid
+ARG gid
+ARG password=rubydev
+
+# setup users and .bashrc
+#   - same pasword for user and root
+#   - color prompt for user and root
+RUN groupadd --gid=$gid --force $group \
+ && useradd --uid=$uid --gid=$gid --shell=/bin/bash --create-home $user \
+ && echo $user:$password | chpasswd \
+ && echo root:$password | chpasswd \
+ && sed -i 's/#force_color_prompt=yes/force_color_prompt=yes/' /home/$user/.bashrc \
+ && sed -i 's/\\u@\\h\\\[\\033\[00m\\\]:\\\[\\033\[01;34m\\\]\\w\\\[\\033\[00m\\\]/\\u \\\[\\033\[01;34m\\\]\\w\\\[\\033\[00m\\\] /' /home/$user/.bashrc \
+ && cp /home/$user/.bashrc /root/.bashrc
+
+ENV \
+    BUNDLE_PATH=/usr/local/bundle \
+    GEM_HOME=/usr/local/bundle \
+    BUNDLE_APP_CONFIG=/usr/local/bundle \
+    BUNDLE_BIN=/usr/local/bundle/bin \
+    BUNDLE_SILENCE_ROOT_WARNING=1 \
+    BUNDLE_CACHE_ALL=1 \
+    LS_OPTIONS='--color=auto' \
+    EDITOR=nano \
+    TERM=${term:-xterm-256color} \
+    SHELL=/bin/bash \
+    LANG=en_US.UTF-8 \
+    LANGUAGE=en_US.UTF-8 \
+    LC_ALL=en_US.UTF-8
+
+RUN chown -R $uid:$gid $BUNDLE_PATH
+
+WORKDIR /opt/project
+
+VOLUME \
+    /home/$user \
+    $BUNDLE_PATH
+
+USER $user
diff --git a/test/pagy/extras/bootstrap_test.rb b/test/pagy/extras/bootstrap_test.rb
index 79f6d515f..277b7fb77 100644
--- a/test/pagy/extras/bootstrap_test.rb
+++ b/test/pagy/extras/bootstrap_test.rb
@@ -4,6 +4,7 @@
 require 'pagy/extras/bootstrap'
 
 describe 'pagy/extras/bootstrap' do
+  require_relative '../../mock_helpers/view'
   let(:view) { MockView.new }
 
   describe '#pagy_bootstrap_nav' do
diff --git a/test/pagy/extras/bulma_test.rb b/test/pagy/extras/bulma_test.rb
index 5dabf755a..e5392d725 100644
--- a/test/pagy/extras/bulma_test.rb
+++ b/test/pagy/extras/bulma_test.rb
@@ -4,6 +4,7 @@
 require 'pagy/extras/bulma'
 
 describe 'pagy/extras/bulma' do
+  require_relative '../../mock_helpers/view'
   let(:view) { MockView.new }
 
   describe '#pagy_bulma_nav' do
diff --git a/test/pagy/extras/foundation_test.rb b/test/pagy/extras/foundation_test.rb
index c6ee90538..24549e1b7 100644
--- a/test/pagy/extras/foundation_test.rb
+++ b/test/pagy/extras/foundation_test.rb
@@ -4,6 +4,7 @@
 require 'pagy/extras/foundation'
 
 describe 'pagy/extras/foundation' do
+  require_relative '../../mock_helpers/view'
   let(:view) { MockView.new }
 
   describe '#pagy_foundation_nav' do
diff --git a/test/pagy/extras/headers_test.rb b/test/pagy/extras/headers_test.rb
index b3850a4e8..00045f6f1 100644
--- a/test/pagy/extras/headers_test.rb
+++ b/test/pagy/extras/headers_test.rb
@@ -13,28 +13,23 @@
     end
     it 'returns the full headers hash' do
       pagy, _records = @controller.send(:pagy, @collection)
-      _(@controller.send(:pagy_headers, pagy)).must_rematch
-      _(@controller.send(:pagy_headers_hash, pagy)).must_rematch
+      _(@controller.send(:pagy_headers, pagy)).must_equal({"Link"=>"<https://example.com:8080/foo?page=1>; rel=\"first\", <https://example.com:8080/foo?page=2>; rel=\"prev\", <https://example.com:8080/foo?page=4>; rel=\"next\", <https://example.com:8080/foo?page=50>; rel=\"last\"", "Current-Page"=>"3", "Page-Items"=>"20", "Total-Pages"=>"50", "Total-Count"=>"1000"})
     end
     it 'returns custom headers hash' do
       pagy, _records = @controller.send(:pagy, @collection, headers:{items:'Per-Page', count: 'Total', pages:false})
-      _(@controller.send(:pagy_headers, pagy)).must_rematch
-      _(@controller.send(:pagy_headers_hash, pagy)).must_rematch
+      _(@controller.send(:pagy_headers, pagy)).must_equal({"Link"=>"<https://example.com:8080/foo?page=1>; rel=\"first\", <https://example.com:8080/foo?page=2>; rel=\"prev\", <https://example.com:8080/foo?page=4>; rel=\"next\", <https://example.com:8080/foo?page=50>; rel=\"last\"", "Per-Page"=>"20", "Total"=>"1000"})
     end
     it 'returns the countless headers hash' do
       pagy, _records = @controller.send(:pagy_countless, @collection)
-      _(@controller.send(:pagy_headers, pagy)).must_rematch
-      _(@controller.send(:pagy_headers_hash, pagy)).must_rematch
+      _(@controller.send(:pagy_headers, pagy)).must_equal({"Link"=>"<https://example.com:8080/foo?page=1>; rel=\"first\", <https://example.com:8080/foo?page=2>; rel=\"prev\", <https://example.com:8080/foo?page=4>; rel=\"next\"", "Current-Page"=>"3", "Page-Items"=>"20"})
     end
     it 'omit prev on first page' do
       pagy, _records = @controller.send(:pagy, @collection, page: 1)
-      _(@controller.send(:pagy_headers, pagy)).must_rematch
-      _(@controller.send(:pagy_headers_hash, pagy)).must_rematch
+      _(@controller.send(:pagy_headers, pagy)).must_equal({"Link"=>"<https://example.com:8080/foo?page=1>; rel=\"first\", <https://example.com:8080/foo?page=2>; rel=\"next\", <https://example.com:8080/foo?page=50>; rel=\"last\"", "Current-Page"=>"1", "Page-Items"=>"20", "Total-Pages"=>"50", "Total-Count"=>"1000"})
     end
     it 'omit next on last page' do
       pagy, _records = @controller.send(:pagy, @collection, page: 50)
-      _(@controller.send(:pagy_headers, pagy)).must_rematch
-      _(@controller.send(:pagy_headers_hash, pagy)).must_rematch
+      _(@controller.send(:pagy_headers, pagy)).must_equal({"Link"=>"<https://example.com:8080/foo?page=1>; rel=\"first\", <https://example.com:8080/foo?page=49>; rel=\"prev\", <https://example.com:8080/foo?page=50>; rel=\"last\"", "Current-Page"=>"50", "Page-Items"=>"20", "Total-Pages"=>"50", "Total-Count"=>"1000"})
     end
   end
 
@@ -46,7 +41,7 @@
     it 'returns the full headers hash' do
       pagy, _records = @controller.send(:pagy, @collection)
       @controller.send(:pagy_headers_merge, pagy)
-      _(@controller.send(:response).headers).must_rematch
+      _(@controller.send(:response).headers).must_equal({"Link"=>"<https://example.com:8080/foo?page=1>; rel=\"first\", <https://example.com:8080/foo?page=2>; rel=\"prev\", <https://example.com:8080/foo?page=4>; rel=\"next\", <https://example.com:8080/foo?page=50>; rel=\"last\"", "Current-Page"=>"3", "Page-Items"=>"20", "Total-Pages"=>"50", "Total-Count"=>"1000"})
     end
   end
 end
diff --git a/test/pagy/extras/i18n_test.rb b/test/pagy/extras/i18n_test.rb
index c6306c890..92e1effd1 100644
--- a/test/pagy/extras/i18n_test.rb
+++ b/test/pagy/extras/i18n_test.rb
@@ -5,6 +5,7 @@
 require 'pagy/extras/i18n'
 
 describe 'pagy/extras/i18n' do
+  require_relative '../../mock_helpers/view'
   let(:view) { MockView.new }
 
   describe '#pagy_t with I18n' do
diff --git a/test/pagy/extras/items_test.rb b/test/pagy/extras/items_test.rb
index 378483e75..5f9031b71 100644
--- a/test/pagy/extras/items_test.rb
+++ b/test/pagy/extras/items_test.rb
@@ -107,6 +107,7 @@ def test_items_vars_params(items, vars, params)
   end
 
   describe 'view_methods' do
+    require_relative '../../mock_helpers/view'
     let(:view) { MockView.new }
 
     describe '#pagy_url_for' do
diff --git a/test/pagy/extras/items_trim_test.rb b/test/pagy/extras/items_trim_test.rb
index a34a9a875..862a6615a 100644
--- a/test/pagy/extras/items_trim_test.rb
+++ b/test/pagy/extras/items_trim_test.rb
@@ -5,6 +5,7 @@
 require 'pagy/extras/trim'
 
 describe 'pagy/extras/items_trim' do
+  require_relative '../../mock_helpers/view'
   let(:view) { MockView.new('http://example.com:3000/foo?') }
 
   describe '#pagy_marked_link' do
diff --git a/test/pagy/extras/materialize_test.rb b/test/pagy/extras/materialize_test.rb
index d628eec0b..fd969c11c 100644
--- a/test/pagy/extras/materialize_test.rb
+++ b/test/pagy/extras/materialize_test.rb
@@ -4,6 +4,7 @@
 require 'pagy/extras/materialize'
 
 describe 'pagy/extras/materialize' do
+  require_relative '../../mock_helpers/view'
   let(:view) { MockView.new }
 
   describe '#pagy_materialize_nav' do
diff --git a/test/pagy/extras/navs_test.rb b/test/pagy/extras/navs_test.rb
index 8150fcf47..a25cac7af 100644
--- a/test/pagy/extras/navs_test.rb
+++ b/test/pagy/extras/navs_test.rb
@@ -4,6 +4,7 @@
 require 'pagy/extras/navs'
 
 describe 'pagy/extras/navs' do
+  require_relative '../../mock_helpers/view'
   let(:view) { MockView.new }
 
   describe '#pagy_nav_js' do
diff --git a/test/pagy/extras/semantic_test.rb b/test/pagy/extras/semantic_test.rb
index 810468ed1..814e79261 100644
--- a/test/pagy/extras/semantic_test.rb
+++ b/test/pagy/extras/semantic_test.rb
@@ -4,6 +4,7 @@
 require 'pagy/extras/semantic'
 
 describe 'pagy/extras/semantic' do
+  require_relative '../../mock_helpers/view'
   let(:view) { MockView.new }
 
   describe '#pagy_semantic_nav' do
diff --git a/test/pagy/extras/shared_json_test.rb b/test/pagy/extras/shared_json_test.rb
index 970a8ead9..76a816718 100644
--- a/test/pagy/extras/shared_json_test.rb
+++ b/test/pagy/extras/shared_json_test.rb
@@ -4,6 +4,7 @@
 require 'pagy/extras/shared'
 
 describe 'pagy/extras/shared_json' do
+  require_relative '../../mock_helpers/view'
   let(:view) { MockView.new('http://example.com:3000/foo?') }
 
   describe '#pagy_json_attr' do
diff --git a/test/pagy/extras/shared_oj_test.rb b/test/pagy/extras/shared_oj_test.rb
index 48ad6293b..86f15bb77 100644
--- a/test/pagy/extras/shared_oj_test.rb
+++ b/test/pagy/extras/shared_oj_test.rb
@@ -5,6 +5,7 @@
 require 'pagy/extras/shared'
 
 describe 'pagy/extras/shared_oj' do
+  require_relative '../../mock_helpers/view'
   let(:view) { MockView.new('http://example.com:3000/foo?') }
 
   describe '#pagy_json_attr' do
diff --git a/test/pagy/extras/standalone_test.rb b/test/pagy/extras/standalone_test.rb
index da46393ba..3f96e7646 100644
--- a/test/pagy/extras/standalone_test.rb
+++ b/test/pagy/extras/standalone_test.rb
@@ -14,6 +14,7 @@ def params
 end
 
 describe 'pagy/extras/standalone' do
+  require_relative '../../mock_helpers/view'
   let(:view) { MockView.new }
 
   describe 'defines #params if missing' do
diff --git a/test/pagy/extras/support_test.rb b/test/pagy/extras/support_test.rb
index c94073cf6..f5df6c1ed 100644
--- a/test/pagy/extras/support_test.rb
+++ b/test/pagy/extras/support_test.rb
@@ -5,6 +5,7 @@
 require 'pagy/countless'
 
 describe 'pagy/extras/support' do
+  require_relative '../../mock_helpers/view'
   let(:view) { MockView.new }
 
   describe '#pagy_prev_url' do
@@ -70,7 +71,7 @@
       _(view.pagy_prev_link(pagy, text: 'PREV', link_extra: 'link-extra')).must_rematch
       _(view.pagy_prev_link(pagy_countless, text: 'PREV', link_extra: 'link-extra')).must_rematch
     end
-    
+
     it 'renders the prev link for page 3' do
       pagy = Pagy.new count: 1000, page: 3
       pagy_countless = Pagy::Countless.new(page: 3).finalize(21)
diff --git a/test/pagy/extras/trim_test.rb b/test/pagy/extras/trim_test.rb
index d1c0c96ae..d2e029f2a 100644
--- a/test/pagy/extras/trim_test.rb
+++ b/test/pagy/extras/trim_test.rb
@@ -3,6 +3,7 @@
 require_relative '../../test_helper'
 require 'pagy/extras/trim'
 
+require_relative '../../mock_helpers/view'
 describe 'pagy/extras/trim' do
 
   describe '#pagy_link_proc' do
diff --git a/test/pagy/extras/uikit_test.rb b/test/pagy/extras/uikit_test.rb
index b19344429..183c292b6 100644
--- a/test/pagy/extras/uikit_test.rb
+++ b/test/pagy/extras/uikit_test.rb
@@ -4,6 +4,7 @@
 require 'pagy/extras/uikit'
 
 describe 'pagy/extras/uikit' do
+  require_relative '../../mock_helpers/view'
   let(:view) { MockView.new }
 
   describe '#pagy_uikit_nav' do
diff --git a/test/pagy/frontend_test.rb b/test/pagy/frontend_test.rb
index 9e0b59c65..9befebe1f 100644
--- a/test/pagy/frontend_test.rb
+++ b/test/pagy/frontend_test.rb
@@ -2,6 +2,7 @@
 
 require_relative '../test_helper'
 
+require_relative '../mock_helpers/view'
 describe 'pagy/frontend' do
   let(:view) { MockView.new }
 
diff --git a/test/test_helper.rb b/test/test_helper.rb
index f8e34a9de..12c6f741e 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -12,6 +12,5 @@
 
 require 'pagy/countless'
 require 'rack'
-require_relative 'mock_helpers/view'
 require_relative 'mock_helpers/controller'
 require 'minitest/autorun'