Simplify ensuredir() with Python3 stdlib features

- Simplify ensuredir() to equivalent os.makedir(name, exist_ok=True)
- Do not check if a directory exists before calling
  ensuredir() (ensuredir() already handles it)
- Add exist_ok argument to path.makedirs() to follow same pattern
- Drop unnecessary .exists() check immediately before .isdir()
- Add tests for ensuredir

1 files changed, 2 insertions, 4 deletions

diff --git a/sphinx/testing/util.py b/sphinx/testing/util.py
index 4b508e1e6..1f575569a 100644
--- a/sphinx/testing/util.py
+++ b/sphinx/testing/util.py
@@ -116,11 +116,9 @@ class SphinxTestApp(application.Sphinx):
         builddir = srcdir / '_build'
         confdir = srcdir
         outdir = builddir.joinpath(buildername)
-        if not outdir.isdir():
-            outdir.makedirs()
+        outdir.makedirs(exist_ok=True)
         doctreedir = builddir.joinpath('doctrees')
-        if not doctreedir.isdir():
-            doctreedir.makedirs()
+        doctreedir.makedirs(exist_ok=True)
         if confoverrides is None:
             confoverrides = {}
         warningiserror = False