test: Only plug in integration-test-setup.sh in interactive mode

If we're not running interactively, there's no point in the features
from integration-test-setup.sh which are intended for interactive
development and debugging so lets skip adding it in that case.

test/integration-test-wrapper.py

@@ -459,6 +459,15 @@ def main() -> None:
             """
         )
 
+    if sys.stderr.isatty():
+        dropin += textwrap.dedent(
+            """
+            [Service]
+            ExecStartPre=/usr/lib/systemd/tests/testdata/integration-test-setup.sh setup
+            ExecStopPost=/usr/lib/systemd/tests/testdata/integration-test-setup.sh finalize
+            """
+        )
+
     cmd = [
         args.mkosi,
         '--directory', os.fspath(args.meson_source_dir),

test/test.service.in

@@ -7,9 +7,7 @@ Before=getty-pre.target
 
 [Service]
 ExecStartPre=rm -f /failed /testok
-ExecStartPre=/usr/lib/systemd/tests/testdata/integration-test-setup.sh setup
 ExecStart=@command@
-ExecStopPost=/usr/lib/systemd/tests/testdata/integration-test-setup.sh finalize
 Type=oneshot
 MemoryAccounting=@memory-accounting@
 StateDirectory=%N