diff --git a/Makefile b/Makefile
index f81c355..edceee8 100644
--- a/Makefile
+++ b/Makefile
@@ -3,7 +3,8 @@ MODULE_big = plparrot
 OBJS= plparrot.o
 DATA_built = plparrot.sql
 REGRESS_OPTS = --dbname=$(PL_TESTDB) --load-language=plpgsql
-TESTS = $(wildcard t/sql/*.sql)
+TESTS = t/sql/test.sql
+PLPERL6_TESTS = t/sql/plperl6.sql
 REGRESS = $(patsubst t/sql/%.sql,%,$(TESTS))
 
 EXTRA_CLEAN =
@@ -60,3 +61,6 @@ endif
 
 test: all
 	psql -AX -f $(TESTS)
+
+test_plperl6: all
+	psql -AX -f $(PLPERL6_TESTS)
diff --git a/plparrot.c b/plparrot.c
index bf584b4..8d06050 100644
--- a/plparrot.c
+++ b/plparrot.c
@@ -397,6 +397,9 @@ plperl6u_call_handler(PG_FUNCTION_ARGS)
 {
     Datum retval;
     interp = p6_interp;
+    if(!interp) {
+        elog(ERROR,"Invalid Parrot interpreter!");
+    }
     retval = plperl6_call_handler(fcinfo);
     interp = trusted_interp;
     return retval;
@@ -409,6 +412,9 @@ plperl6_call_handler(PG_FUNCTION_ARGS)
     TriggerData *tdata;
 
     interp = p6_interp;
+    if(!interp) {
+        elog(ERROR,"Invalid Parrot interpreter!");
+    }
     PG_TRY();
     {
         if (CALLED_AS_TRIGGER(fcinfo)) {
diff --git a/t/sql/plperl6.sql b/t/sql/plperl6.sql
new file mode 100644
index 0000000..a406425
--- /dev/null
+++ b/t/sql/plperl6.sql
@@ -0,0 +1,34 @@
+\unset ECHO
+\set QUIET 1
+-- Turn off echo and keep things quiet.
+-- Format the output for nice TAP.
+\pset format unaligned
+\pset tuples_only true
+\pset pager
+-- Revert all changes on failure.
+\set ON_ERROR_ROLLBACK 1
+\set ON_ERROR_STOP true
+
+-- Load the TAP functions.
+BEGIN;
+\i pgtap.sql
+\i plparrot.sql
+
+-- Plan the tests.
+SELECT plan(3);
+
+CREATE FUNCTION test_void_plperl6(integer) RETURNS void AS $$ Nil $$ LANGUAGE plperl6;
+
+CREATE FUNCTION test_int_plperl6(integer) RETURNS int AS $$ 42 $$ LANGUAGE plperl6;
+
+CREATE FUNCTION test_float_plperl6(integer) RETURNS float AS $$ 5.0 $$ LANGUAGE plperl6;
+
+
+select is(test_int_plperl6(89),42,'Return an integer from PL/Perl6');
+select is(test_void_plperl6(42)::text,''::text,'Return nothing from PL/Perl6');
+select is(test_float_plperl6(2),5.0::float,'Return a float from PL/Perl6');
+
+-- Finish the tests and clean up.
+SELECT * FROM finish();
+
+rollback;
diff --git a/t/sql/test.sql b/t/sql/test.sql
index 12c12a0..8a41411 100644
--- a/t/sql/test.sql
+++ b/t/sql/test.sql
@@ -15,7 +15,7 @@ BEGIN;
 \i plparrot.sql
 
 -- Plan the tests.
-SELECT plan(33);
+SELECT plan(31);
 
 CREATE OR REPLACE FUNCTION create_plparrot()
 RETURNS BOOLEAN
@@ -25,12 +25,6 @@ CREATE LANGUAGE plparrot;
 SELECT true;
 $$;
 
-CREATE FUNCTION test_void_plperl6(integer) RETURNS void AS $$ Nil $$ LANGUAGE plperl6;
-
-CREATE FUNCTION test_int_plperl6(integer) RETURNS int AS $$ 42 $$ LANGUAGE plperl6;
-
-CREATE FUNCTION test_float_plperl6(integer) RETURNS float AS $$ 5.0 $$ LANGUAGE plperl6;
-
 CREATE FUNCTION test_void() RETURNS void AS $$
     .return()
 $$ LANGUAGE plparrot;
@@ -266,11 +260,6 @@ select is(test_timestamptz_out('1999-01-08 04:05:06+02'),'1999-01-08 04:05:06+02
 select is(test_time_in('04:05:06'),1,'We can pass a time in');
 select is(test_time_out('04:05:06'),'04:05:06','We can return a time');
 
-select is(test_int_plperl6(89),42,'Return an integer from PL/Perl6');
-select is(test_void_plperl6(42)::text,''::text,'Return nothing from PL/Perl6');
-select is(test_float_plperl6(2),5.0::float,'Return a float from PL/Perl6');
-
-
 -- not loading io opcodes, they are deprecated
 --select isnt(test_open_plparrotu(), 42, 'open opcode is not mocked in plperlu');