[e2e] Move the smoke tests to a new root folder "e2e_tests/"

e2e_tests/sandbox_basic_test.py

@@ -0,0 +1,32 @@
+from __future__ import annotations
+import sys
+import multiprocessing
+from pathlib import Path
+
+project_root = Path(__file__).parent.parent
+for python_path in [str(project_root), str(project_root / "src")]:
+    sys.path.append(python_path)
+
+
+def launch_sandbox_script():
+    from sandbox.basic import app as basic_app
+
+    basic_app.run()
+
+
+# The following line seems to be required in order to have this work in the MacOS part
+# of our CI - despite the fact that Python docs say that this function
+# "has no effect when invoked on any operating system other than Windows" 🤔
+multiprocessing.freeze_support()
+
+process = multiprocessing.Process(target=launch_sandbox_script, daemon=True)
+process.start()
+
+process.join(timeout=2)
+
+process_still_running = process.exitcode is None
+process_was_able_to_run_without_errors = process_still_running
+if process_still_running:
+    process.kill()
+
+sys.exit(0 if process_was_able_to_run_without_errors else 1)