diff --git a/CLAUDE.md b/CLAUDE.md
index a7aaeec..d3e8f7c 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -39,7 +39,7 @@ Drei Wächter prüfen das. `core/clippy.toml` sperrt Pfade wie `std::collections
 - GDScript mit Typangaben schreiben (`var x := …`, Rückgabetypen an jeder Funktion).
 - Eingabeaktionen legt `game/scripts/input_setup.gd` an, nicht `project.godot`.
 - Alle Texte, die Spieler sehen, stehen in `game/i18n/texts.csv` (Deutsch und Englisch) und werden über `tr()` geholt.
-- Tests, die Dateien schreiben, nutzen `TestFiles.temporary_dir()`, nie den echten Benutzerordner.
+- Tests, die Dateien schreiben, nutzen `TestFiles.temporary_dir()` (Ordner unter `user://tests`), nie die echten Dateien des Spielers.
 - Godot erzeugt beim Import zu jedem Skript eine `.uid`-Datei. Sie gehört ins Archiv. Der Ordner `game/.godot/` gehört nicht hinein.
 
 ## Prüfen
diff --git a/game/tests/run_tests.gd b/game/tests/run_tests.gd
index 5a0ea89..b9cc7d0 100644
--- a/game/tests/run_tests.gd
+++ b/game/tests/run_tests.gd
@@ -44,6 +44,11 @@ func _initialize() -> void:
 
 
 func _run_all() -> void:
+	# Remove what runs that stopped early left behind, before the error
+	# counter starts. Only if the folder exists, because Godot reports an
+	# error when it lists a missing one.
+	if DirAccess.dir_exists_absolute(TestFiles.ROOT):
+		TestFiles.remove_dir(TestFiles.ROOT)
 	var counter := ErrorCounter.new()
 	OS.add_logger(counter)
 	var passed := 0
diff --git a/game/tests/support/test_files.gd b/game/tests/support/test_files.gd
index 09d77d3..55fd5bd 100644
--- a/game/tests/support/test_files.gd
+++ b/game/tests/support/test_files.gd
@@ -1,18 +1,29 @@
 class_name TestFiles
 extends RefCounted
-## Temporary folders below user://tests for tests that write files, so that
-## tests never touch the player's real key, save or recordings.
+## Temporary folders below user://tests for tests that write files. That
+## folder lies inside the game's real user folder, next to the player's own
+## key, save and recordings, so nothing outside it may be deleted here.
+
+## The only folder the tests write to and remove_dir deletes from.
+const ROOT := "user://tests"
 
 
 static func temporary_dir(label: String) -> String:
-	var path := "user://tests".path_join("%s-%d" % [label, Time.get_ticks_usec()])
+	var path := ROOT.path_join("%s-%d" % [label, Time.get_ticks_usec()])
 	DirAccess.make_dir_recursive_absolute(path)
 	return path
 
 
+## Deletes the folder `path` with everything in it. Refuses every path that is
+## not ROOT or below it, with an error and without deleting anything: a wrong
+## argument must never delete the player's real files.
 static func remove_dir(path: String) -> void:
-	for file in DirAccess.get_files_at(path):
-		DirAccess.remove_absolute(path.path_join(file))
-	for directory in DirAccess.get_directories_at(path):
-		remove_dir(path.path_join(directory))
-	DirAccess.remove_absolute(path)
+	var clean := path.simplify_path()
+	if clean != ROOT and not clean.begins_with(ROOT + "/"):
+		push_error("TestFiles.remove_dir refuses %s: it is not %s or below it" % [path, ROOT])
+		return
+	for file in DirAccess.get_files_at(clean):
+		DirAccess.remove_absolute(clean.path_join(file))
+	for directory in DirAccess.get_directories_at(clean):
+		remove_dir(clean.path_join(directory))
+	DirAccess.remove_absolute(clean)