From 0d8f52bce0c75cfdb842598c080119536a7278cd Mon Sep 17 00:00:00 2001
From: Daniel Watkins <oddbloke@ubuntu.com>
Date: Fri, 19 Jun 2020 14:29:09 -0400
Subject: [PATCH] HACKING.rst: add strpath gotcha to testing gotchas section

---
 HACKING.rst | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/HACKING.rst b/HACKING.rst
index 81e6c2660ec..47ac6a86d77 100644
--- a/HACKING.rst
+++ b/HACKING.rst
@@ -227,6 +227,14 @@ The following guidelines should be followed:
     * ``tmpdir_factory``
     * ``tmpdir``
 
+  * On xenial, the objects returned by the ``tmpdir`` fixture cannot be
+    used where paths are required; they are rejected as invalid paths.
+    You must instead use their ``.strpath`` attribute.
+
+    * For example, instead of
+      ``util.write_file(tmpdir.join("some_file"), ...)``, you should
+      write ``util.write_file(tmpdir.join("some_file").strpath, ...)``.
+
 * Variables/parameter names for ``Mock`` or ``MagicMock`` instances
   should start with ``m_`` to clearly distinguish them from non-mock
   variables