PRESUBMIT: run fmap unittests

These are fast so shouldn't be a problem to run.

BUG=chromium:982465
TEST=`repo upload` runs these unittests

Change-Id: Ib32e56e28ed0b349370d46553a032e99ff92791c
Reviewed-on: https://chromium-review.googlesource.com/1693882
Tested-by: Mike Frysinger <vapier@chromium.org>
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Duncan Laurie <dlaurie@google.com>
diff --git a/PRESUBMIT.cfg b/PRESUBMIT.cfg
index 420337e..8238211 100644
--- a/PRESUBMIT.cfg
+++ b/PRESUBMIT.cfg
@@ -1,5 +1,8 @@
 # This project uses BSD/GPLv2 for the license and tabs for indentation.
 
+[Hook Scripts]
+fmap_unittest py2 = python2 ./fmap_unittest.py
+
 [Hook Overrides]
 cros_license_check: false
 tab_check: false