diff --git a/.github/workflows/build-and-test.yml b/.github/workflows/build-and-test.yml
index 42b00cf..89963db 100644
--- a/.github/workflows/build-and-test.yml
+++ b/.github/workflows/build-and-test.yml
@@ -21,10 +21,48 @@ jobs:
       - name: Install dependencies
         shell: bash
         run: |
-          sudo apt-get install libxi-dev
+          sudo apt-get install libgl-dev libxi-dev \
+            libx11-dev xserver-xorg-dev xorg-dev
       # kle tests not triggered from main,
       # must figure out how to properly zig test
       - run: |
+          zig build
           zig build test
           zig test src/kle.zig
           zig test src/spsc_queue.zig
+      - uses: actions/upload-artifact@v4
+        if: always()
+        with:
+          name: klawa
+          path: zig-out/bin/klawa
+          retention-days: 2
+          if-no-files-found: error
+
+  run-functional-tests:
+    name: Run functional tests
+    needs:
+    - build-and-test
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/download-artifact@v4
+        with:
+          name: klawa
+          path: zig-out/bin
+      - name: Install dependencies
+        shell: bash
+        run: |
+          sudo apt-get install ffmpeg xdotool xvfb
+      - name: Run tests
+        shell: bash
+        run: |
+          chmod +x zig-out/bin/klawa
+          ldd zig-out/bin/klawa
+          cd tests && ./test.sh
+      - uses: actions/upload-artifact@v4
+        if: always()
+        with:
+          name: output.webm
+          path: tests/output.webm
+          retention-days: 2
+          if-no-files-found: error
diff --git a/.justfile b/.justfile
index 7143de7..17b9ebd 100644
--- a/.justfile
+++ b/.justfile
@@ -37,3 +37,6 @@ test-kle:
 
 test-queue:
   zig test src/spsc_queue.zig
+
+functional-tests:
+  cd tests && ./test.sh
diff --git a/tests/test.sh b/tests/test.sh
new file mode 100755
index 0000000..8bfed9c
--- /dev/null
+++ b/tests/test.sh
@@ -0,0 +1,45 @@
+#!/bin/bash
+
+set -e
+set -u
+
+SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+
+# TODO: should check if free:
+FAKE_DISPLAY=:99
+APP=${SCRIPT_DIR}/../zig-out/bin/klawa
+TEST_EVENTS=test_events.bin
+TEST_RENDER_DIR=render-out
+
+# TODO: add option to choose display, for local development Xephyr is better
+# but on CI Xvfb is required
+
+#Xephyr -br -ac -noreset -screen 960x320 $FAKE_DISPLAY &
+#DISPLAY_PID=$!
+
+Xvfb -ac $FAKE_DISPLAY -screen 0 960x320x24 > /dev/null 2>&1 &
+DISPLAY_PID=$!
+
+# wait for display
+sleep 1
+
+DISPLAY=$FAKE_DISPLAY $APP --record $TEST_EVENTS &
+APP_PID=$!
+
+# wait for tested app
+sleep 1
+
+# simulate some input
+DISPLAY=$FAKE_DISPLAY xdotool type --delay 500 "this is klawa app"
+kill -9 $APP_PID
+
+mkdir $TEST_RENDER_DIR
+DISPLAY=$FAKE_DISPLAY $APP --replay $TEST_EVENTS --render $TEST_RENDER_DIR
+kill -9 $DISPLAY_PID
+
+rm $TEST_EVENTS
+
+cd $TEST_RENDER_DIR && ffmpeg -y -framerate 60 -s 960x320 -pix_fmt rgba -i "frame%05d.raw" -c:v libvpx-vp9 ../output1.webm
+cd -
+
+rm -rf $TEST_RENDER_DIR