Apply batched suggestions from code review

Co-authored-by: Victor Stinner <vstinner@python.org>

Author: StanFromIreland

Lib/test/test_external_inspection.py

@@ -772,7 +772,7 @@ def func():
             text=True,
             timeout=SHORT_TIMEOUT,
         )
-        self.assertEqual(result.returncode, 0, result.stderr)
+        self.assertEqual(result.returncode, 0, result)
         self.assertIn("<unknown function>", result.stdout)
 
     @skip_if_not_supported

Modules/_testinternalcapi.c

@@ -2060,12 +2060,12 @@ unicode_transformdecimalandspacetoascii(PyObject *self, PyObject *arg)
 static PyObject *
 new_invalid_str(PyObject *self, PyObject *Py_UNUSED(ignored))
 {
-    PyObject *str = PyUnicode_New(2, 0x10FFFF);
+    PyObject *str = PyUnicode_New(2, _Py_MAX_UNICODE);
     if (str == NULL) {
         return NULL;
     }
-    PyUnicode_4BYTE_DATA(str)[0] = 0x110000;
-    PyUnicode_4BYTE_DATA(str)[1] = 0x110000;
+    PyUnicode_4BYTE_DATA(str)[0] = _Py_MAX_UNICODE + 1;
+    PyUnicode_4BYTE_DATA(str)[1] = _Py_MAX_UNICODE + 2;
     return str;
 }