The following Makefiles are identical (except for year of creation):
policy_ChromeOsLockOnIdleSuspend/src/Makefile
policy_CookiesAllowedForUrls/src/Makefile
policy_CookiesBlockedForUrls/src/Makefile
policy_CookiesSessionOnlyForUrls/src/Makefile
policy_DisableScreenshots/src/Makefile
policy_EditBookmarksEnabled/src/Makefile
policy_ForceGoogleSafeSearch/src/Makefile
policy_ForceYouTubeSafetyMode/src/Makefile
policy_ImagesAllowedForUrls/src/Makefile
policy_ImagesBlockedForUrls/src/Makefile
policy_JavaScriptAllowedForUrls/src/Makefile
policy_JavaScriptBlockedForUrls/src/Makefile
policy_ManagedBookmarks/src/Makefile
policy_NotificationsAllowedForUrls/src/Makefile
policy_NotificationsBlockedForUrls/src/Makefile
policy_PluginsAllowedForUrls/src/Makefile
policy_PluginsBlockedForUrls/src/Makefile
policy_PopupsAllowedForUrls/src/Makefile
policy_PopupsBlockedForUrls/src/Makefile
policy_PowerManagementIdleSettings/src/Makefile
policy_ProxySettings/src/Makefile
policy_RestoreOnStartupURLs/src/Makefile
policy_URLBlacklist/src/Makefile
policy_URLWhitelist/src/Makefile


All these autotests inherit from EnterprisePolicyTest in enterprise_policy_base.py. It should be possible to keep one template Makefile in cros/enterprise/Makefile, and copy this to the src/ directory for each autotest during setup.

I tried to modify the setup method like so:
     def setup(self):
         if not os.path.isdir(self.srcdir):
             os.mkdir(self.srcdir)
             makefile = 'Makefile'
             make_src = os.path.join(os.path.dirname(__file__), makefile)
             make_dst = os.path.join(self.srcdir, makefile)
             shutil.copyfile(make_src, make_dst)

         os.chdir(self.srcdir)
         utils.make()

Sadly this didn't work.