test: plug a memleak in the python tests

We need to free the list returned

test/__init__.py

@@ -45,7 +45,7 @@ class _Api:
 
     @property
     def basename(self) -> str:
-        return self.name[len(PREFIX) :]
+        return self.name.removeprefix(PREFIX)
 
 
 @dataclass
@@ -58,6 +58,33 @@ def basename(self) -> str:
         return self.name.removeprefix("WACOM_").removeprefix("W")
 
 
+class GlibC:
+    _lib = None
+
+    _api_prototypes: List[_Api] = [
+        _Api(name="free", args=(c_void_p,), return_type=None),
+    ]
+
+    @staticmethod
+    def _cdll():
+        return ctypes.CDLL("libc.so.6", use_errno=True)
+
+    @classmethod
+    def _load(cls):
+        cls._lib = cls._cdll()
+        for api in cls._api_prototypes:
+            func = getattr(cls._lib, api.name)
+            func.argtypes = api.args
+            func.restype = api.return_type
+            setattr(cls, api.basename, func)
+
+    @classmethod
+    def instance(cls):
+        if cls._lib is None:
+            cls._load()
+        return cls
+
+
 class LibWacom:
     """
     libwacom.so wrapper. This is a singleton ctypes wrapper into libwacom.so with
@@ -716,7 +743,9 @@ def new_from_builder(
 
     def list_devices(self) -> List[WacomDevice]:
         devices = self.libwacom_list_devices_from_database(self.db, 0)
-        return [
+        devs = [
             WacomDevice(d, destroy=False)
             for d in itertools.takewhile(lambda ptr: ptr is not None, devices)
         ]
+        GlibC.instance().free(devices)
+        return devs