Prevent race conditions from failing tests during 'import usepkgs'

1 files changed, 7 insertions, 0 deletions

diff --git a/tox.ini b/tox.ini
index ea36b803..4e0b9edd 100644
--- a/tox.ini
+++ b/tox.ini
@@ -38,6 +38,13 @@ commands =
     # Remove the C extension so that we can test the PyTracer
     python igor.py zip_mods install_egg remove_extension
 
+    # When running parallel tests, many processes might all try to import the
+    # same modules at once. This should be safe, but especially on Python 3.3,
+    # this caused a number of test failures trying to import usepkgs.  To
+    # prevent the race condition, pre-compile the tests/modules directory.
+    py33: python -m compileall -q -f tests/modules
+    py33: python -c "import time; time.sleep(1.1)"
+
     # Test with the PyTracer
     python igor.py test_with_tracer py {posargs}