Backport PR #13181: create ipython_dir if not exists

IPython/core/tests/test_paths.py

@@ -160,6 +160,10 b' def test_get_ipython_dir_7():'
 @skip_win32
 def test_get_ipython_dir_8():
     """test_get_ipython_dir_8, test / home directory"""
+    if not os.access("/", os.W_OK):
+        # test only when HOME directory actually writable
+        return
+
     with patch.object(paths, '_writable_dir', lambda path: bool(path)), \
             patch.object(paths, 'get_xdg_dir', return_value=None), \
             modified_env({

IPython/paths.py

@@ -66,6 +66,8 b' def get_ipython_dir() -> str:'
             warn("IPython parent '{0}' is not a writable location,"
                     " using a temp directory.".format(parent))
             ipdir = tempfile.mkdtemp()
+        else:
+            os.makedirs(ipdir)
     assert isinstance(ipdir, str), "all path manipulation should be str(unicode), but are not."
     return ipdir