diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3192fde9..916be080 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -135,26 +135,7 @@ jobs:
           flatpak run --command=flatpak-builder-lint org.flatpak.Builder//localtest --exceptions repo repo
 
       - name: Perform Flatmanager checks
-        run: |
-          export FLAT_MANAGER_BUILD_ID=0 FLAT_MANAGER_URL=http://localhost:9001 FLAT_MANAGER_TOKEN=foo
-          cd tests/repo/min_success_metadata/gui-app
-          mkdir -p repo/appstream/x86_64
-          mv -v builddir/files/share/app-info/xmls/org.flathub.gui.xml.gz repo/appstream/x86_64/appstream.xml.gz
-          nohup python ../../../test_httpserver.py &
-          sleep 15
-          errors1="$(flatpak run --command=flatpak-builder-lint org.flatpak.Builder//localtest --exceptions repo repo|jq -r '.errors|.[]'|xargs)"
-          if [ "${errors1}" == "appstream-no-flathub-manifest-key" ]; then echo "Pass"; else echo "Failed, $errors1" && false; fi
-          gzip -df repo/appstream/x86_64/appstream.xml.gz || true
-          xmlstarlet ed --subnode "/components/component" --type elem -n custom --subnode "/components/component/custom" --type elem -n \
-            value -v "https://raw.githubusercontent.com/flathub-infra/flatpak-builder-lint/240fe03919ed087b24d941898cca21497de0fa49/tests/repo/min_success_metadata/gui-app/org.flathub.gui.yaml" \
-            repo/appstream/x86_64/appstream.xml|xmlstarlet ed --insert //custom/value \
-            --type attr -n key -v flathub::manifest >> repo/appstream/x86_64/appstream-out.xml
-          rm -vf repo/appstream/x86_64/appstream.xml  repo/appstream/x86_64/appstream.xml.gz
-          mv -v repo/appstream/x86_64/appstream-out.xml repo/appstream/x86_64/appstream.xml
-          gzip repo/appstream/x86_64/appstream.xml || true
-          errors2="$(flatpak run --command=flatpak-builder-lint org.flatpak.Builder//localtest --exceptions repo repo|jq -r '.errors|.[]'|xargs)"
-          if [ "${errors2}" == "" ]; then echo "Pass"; else echo "Failed, $errors2" && false; fi
-          python ../../../test_httpserver.py --stop
+        run: sh -c tests/flatmanager.sh
 
       - name: Set up appstreamcli
         run: |
diff --git a/README.md b/README.md
index e8b5ac34..9107468d 100644
--- a/README.md
+++ b/README.md
@@ -141,6 +141,13 @@ to run tests:
 poetry run pytest -v tests
 ```
 
+An additional Flat manager test can be run when modifying code relying
+on the flatmanager check using
+
+```sh
+./tests/flatmanager.sh
+```
+
 ## Usage
 
 ```
diff --git a/tests/flatmanager.sh b/tests/flatmanager.sh
new file mode 100755
index 00000000..796f7a43
--- /dev/null
+++ b/tests/flatmanager.sh
@@ -0,0 +1,128 @@
+#!/bin/sh
+
+top_dir="$(pwd)"
+
+checkcmd() {
+    if ! command -v "$1" > /dev/null 2>&1; then
+        echo "$1 not found"
+        exit 1
+    fi
+}
+
+checkcmd "python"
+checkcmd "gzip"
+checkcmd "jq"
+checkcmd "xmlstarlet"
+checkcmd "git"
+checkcmd "flatpak-builder" 
+checkcmd "flatpak"
+checkcmd "ostree"
+
+if [ "$GITHUB_ACTIONS" = "true" ]; then
+	checkcmd "dbus-run-session"
+fi
+
+arch="$(flatpak --default-arch)"
+check_exists="$(flatpak info org.flatpak.Builder//localtest)"
+
+files="docker/rewrite-manifest.py docker/flatpak-builder-lint-deps.json tests/repo/min_success_metadata/gui-app/org.flathub.gui.yaml tests/test_httpserver.py"
+for item in ${files}; do
+	if [ ! -f "$item" ]; then
+		echo "$item does not exist."
+		exit 1
+	fi
+done
+
+if [ "$GITHUB_ACTIONS" = "true" ]; then
+	checkcmd "dbus-run-session"
+fi
+
+if [ -z "$GITHUB_ACTIONS" ]; then
+	echo "Not inside GitHub CI. Trying to build org.flatpak.Builder//localtest"
+	flatpak remote-add --user --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
+
+	if [ -d "build/org.flatpak.Builder" ]; then
+		rm -rf build/org.flatpak.Builder
+	fi
+	
+	git clone --depth=1 --branch master --recursive --single-branch https://github.com/flathub/org.flatpak.Builder.git build/org.flatpak.Builder
+	cd build && python3 ../docker/rewrite-manifest.py && cd org.flatpak.Builder || exit
+	rm -v flatpak-builder-lint-deps.json && cp -v ../../docker/flatpak-builder-lint-deps.json .
+	git config protocol.file.allow always
+	flatpak-builder --user --force-clean --repo=repo --install-deps-from=flathub --default-branch=localtest --ccache --install builddir org.flatpak.Builder.json
+	flatpak run org.flatpak.Builder//localtest --version
+fi
+
+if [ "${check_exists}" ]; then
+	cd "$top_dir" || exit
+	rm -rf tests/repo/min_success_metadata/gui-app/builddir tests/repo/min_success_metadata/gui-app/repo tests/repo/min_success_metadata/gui-app/.flatpak-builder
+	cd tests/repo/min_success_metadata/gui-app || exit
+
+	if [ "$GITHUB_ACTIONS" = "true" ]; then
+		dbus-run-session flatpak run org.flatpak.Builder//localtest --verbose --user --force-clean --repo=repo --mirror-screenshots-url=https://dl.flathub.org/media --install-deps-from=flathub --ccache builddir org.flathub.gui.yaml
+	else
+		flatpak run org.flatpak.Builder//localtest --verbose --user --force-clean --repo=repo --mirror-screenshots-url=https://dl.flathub.org/media --install-deps-from=flathub --ccache builddir org.flathub.gui.yaml
+	fi
+
+
+	mkdir -p builddir/files/share/app-info/media
+	ostree commit --repo=repo --canonical-permissions --branch=screenshots/"${arch}" builddir/files/share/app-info/media
+	export FLAT_MANAGER_BUILD_ID=0 FLAT_MANAGER_URL=http://localhost:9001 FLAT_MANAGER_TOKEN=foo
+	mkdir -p repo/appstream/x86_64
+	mv -v builddir/files/share/app-info/xmls/org.flathub.gui.xml.gz repo/appstream/"${arch}"/appstream.xml.gz
+	nohup python ../../../test_httpserver.py &
+	sleep 15
+
+	errors1="$(flatpak run --command=flatpak-builder-lint org.flatpak.Builder//localtest --exceptions repo repo|jq -r '.errors|.[]'|xargs)" && tests_run="yes"
+	if [ "${errors1}" = "appstream-no-flathub-manifest-key" ]; then
+		echo "Test1: Pass"
+		test_code="test_passed"
+	else
+		echo "Test1: Failed, $errors1"
+		test_code="test_failed"
+	fi
+
+	gzip -df repo/appstream/"${arch}"/appstream.xml.gz || true
+	xmlstarlet ed --subnode "/components/component" --type elem -n custom --subnode "/components/component/custom" --type elem -n value -v "https://raw.githubusercontent.com/flathub-infra/flatpak-builder-lint/240fe03919ed087b24d941898cca21497de0fa49/tests/repo/min_success_metadata/gui-app/org.flathub.gui.yaml" repo/appstream/"${arch}"/appstream.xml|xmlstarlet ed --insert //custom/value --type attr -n key -v flathub::manifest >> repo/appstream/x86_64/appstream-out.xml
+	rm -vf repo/appstream/"${arch}"/appstream.xml  repo/appstream/"${arch}"/appstream.xml.gz
+	mv -v repo/appstream/"${arch}"/appstream-out.xml repo/appstream/"${arch}"/appstream.xml
+	gzip repo/appstream/"${arch}"/appstream.xml || true
+
+	errors2="$(flatpak run --command=flatpak-builder-lint org.flatpak.Builder//localtest --exceptions repo repo|jq -r '.errors|.[]'|xargs)" && tests_run="yes"
+	if [ "${errors2}" = "" ]; then
+		echo "Test2: Pass"
+		test_code="test_passed"
+	else
+		echo "Test2: Failed, $errors2"
+		test_code="test_failed"
+	fi
+
+	python ../../../test_httpserver.py --stop
+
+	if [ -z "$GITHUB_ACTIONS" ]; then
+		flatpak remove -y org.flatpak.Builder//localtest
+		flatpak uninstall --user --unused -y
+	fi
+
+	cd "$top_dir" || exit
+
+	rm -rf tests/repo/min_success_metadata/gui-app/nohup.out build tests/repo/min_success_metadata/gui-app/builddir tests/repo/min_success_metadata/gui-app/repo tests/repo/min_success_metadata/gui-app/.flatpak-builder
+	unset FLAT_MANAGER_BUILD_ID
+	unset FLAT_MANAGER_URL
+	unset FLAT_MANAGER_TOKEN
+fi
+
+if [ "${test_code}" = "test_passed" ]; then
+	printf "\n\n"
+	echo "Tests passed ✅✅"
+	exit 0
+elif [ -z "${tests_run}" ]; then
+	echo "Tests did not run 🚨🚨"
+	exit 1
+elif [ "${test_code}" = "test_failed" ]; then
+	echo "Tests failed 🚨🚨"
+	exit 1
+else
+	echo "Error occurred 🚨🚨"
+	exit 1
+fi