diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c
index ab9467e..3a6dcd6 100644
--- a/Modules/_testcapimodule.c
+++ b/Modules/_testcapimodule.c
@@ -1425,7 +1425,7 @@
         return NULL;
     }
 
-    if (PyUnicode_GET_SIZE(wide) != PyUnicode_GET_SIZE(utf8)) {
+    if (PyUnicode_GET_LENGTH(wide) != PyUnicode_GET_LENGTH(utf8)) {
         Py_DECREF(wide);
         Py_DECREF(utf8);
         return raiseTestError("test_widechar",