Issue #15533: Clarify docs and add tests for subprocess.Popen()'s cwd argument.
diff --git a/Doc/library/subprocess.rst b/Doc/library/subprocess.rst
index 9c03e06..e4c1ad4 100644
--- a/Doc/library/subprocess.rst
+++ b/Doc/library/subprocess.rst
@@ -415,10 +415,10 @@
.. versionadded:: 3.2
The *pass_fds* parameter was added.
- If *cwd* is not ``None``, the child's current directory will be changed to *cwd*
- before it is executed. Note that this directory is not considered when
- searching the executable, so you can't specify the program's path relative to
- *cwd*.
+ If *cwd* is not ``None``, the function changes the working directory to
+ *cwd* before executing the child. In particular, the function looks for
+ *executable* (or for the first item in *args*) relative to *cwd* if the
+ executable path is a relative path.
If *restore_signals* is True (the default) all signals that Python has set to
SIG_IGN are restored to SIG_DFL in the child process before the exec.