Also run demo app as headless on CI

.github/workflows/build.yml

@@ -155,6 +155,8 @@ jobs:
       run: cmake --build build --parallel $(nproc) --config Release
     - name: Run headless test
       run: pushd build && ctest --output-on-failure
+    - name: Run integration test on sample app
+      run: pushd build/examples && python3 run-tests-selenium.py 
 
   build-on-windows-for-cppcli:
     runs-on: windows-latest

examples/ts/run-tests-selenium.py

@@ -0,0 +1,53 @@
+#! /usr/bin/env python3
+
+from http.server import HTTPServer, SimpleHTTPRequestHandler
+from selenium import webdriver
+from selenium.webdriver.common.by import By
+from selenium.webdriver.chrome.service import Service
+import sys
+import time
+import threading
+
+port = "8050"
+httpd = HTTPServer(("127.0.0.1", int(port)), SimpleHTTPRequestHandler)
+
+def run_server():
+    print("Serving HTTP on localhost port " + port + " (http://localhost:" + port + "/) ...")
+    httpd.serve_forever()
+
+server_thread = threading.Thread(target=run_server)
+server_thread.start()
+
+service = Service(executable_path=r'/usr/bin/chromedriver')
+options = webdriver.ChromeOptions()
+options.add_argument('--headless')
+options.add_argument('--no-sandbox')
+options.add_argument('--disable-dev-shm-usage')
+options.add_argument('--disable-gpu')
+driver = webdriver.Chrome(service=service, options=options)
+print(f"connecting web driver to http://localhost:{port}/")
+driver.get(f"http://localhost:{port}/demo.html")
+asc_button = driver.find_element(By.ID, "btnAsc")
+desc_button = driver.find_element(By.ID, "btnDesc")
+
+asc_button.click()
+print("Wait for Asc button press")
+time.sleep(0.5)
+value =  driver.find_element(By.ID, "txt").get_attribute("value")
+is_ascending_ok = value == "item1\nitem2\nitem3\nitem4\nitem5"
+print(f"text area on Sort Asc pressed:\n{value}")
+desc_button.click()
+print("Wait for Desc button press")
+time.sleep(0.5)
+value = driver.find_element(By.ID, "txt").get_attribute("value")
+print(f"text area on Sort Desc pressed:\n{value}")
+is_descending_ok = value == "item5\nitem4\nitem3\nitem2\nitem1"
+
+driver.quit()
+httpd.shutdown()
+server_thread.join()
+if is_ascending_ok and is_descending_ok:
+    exit(0)
+print(f"is_ascending_ok = {is_ascending_ok}")
+print(f"is_descending_ok = {is_descending_ok}")
+exit(1)