Issue #6152: New option '-j'/'--multiprocess' for regrtest allows running

regression tests in parallel, shortening the total runtime.

Doc/whatsnew/2.7.rst

@@ -654,6 +654,12 @@ Other Changes and Fixes
   The :option:`-r` option also now reports the seed that was used
   (Added by Collin Winter.)
 
+* The :file:`regrtest.py` script now takes a :option:`-j` switch
+  that takes an integer specifying how many tests run in parallel. This
+  allows to shorten the total runtime on multi-core machines.
+  This option is compatible with several other options, including the
+  :option:`-R` switch which is known to produce long runtimes.
+  (Added by Antoine Pitrou, :issue:`6152`.)
 
 .. ======================================================================
 

Lib/test/test_support.py

@@ -378,6 +378,10 @@ else:
                 'Unicode filename tests may not be effective' \
                 % TESTFN_UNICODE_UNENCODEABLE
 
+# Disambiguate TESTFN for parallel testing, while letting it remain a valid
+# module name.
+TESTFN = "{0}_{1}_tmp".format(TESTFN, os.getpid())
+
 # Make sure we can write to TESTFN, try in /tmp if we can't
 fp = None
 try:

Misc/NEWS

@@ -1104,6 +1104,9 @@ Extension Modules
 Tests
 -----
 
+- Issue #6152: New option '-j'/'--multiprocess' for regrtest allows running
+  regression tests in parallel, shortening the total runtime.
+
 - Issue #5354: New test support function import_fresh_module() makes
   it easy to import both normal and optimised versions of modules.
   test_heapq and test_warnings have been adjusted to use it, tests for