diff --git a/configure.ac b/configure.ac
index 320c250..d843efb 100644
--- a/configure.ac
+++ b/configure.ac
@@ -156,6 +156,8 @@
 fi
 AM_CONDITIONAL(WITH_PYTHON, [test "$have_python" = "yes"])
 
+AC_PATH_PROG([TRIAL], [trial])
+
 AX_THRIFT_LIB(perl, [Perl], yes)
 if test "$with_perl" = "yes"; then
   AC_PATH_PROG([PERL], [perl])
@@ -379,6 +381,7 @@
   test/Makefile
   test/hs/Makefile
   test/py/Makefile
+  test/py.twisted/Makefile
   test/rb/Makefile
 ])