add files for modularity-testing-framework based tests

Currently there seems to be an issue with passing the test command line
to the shell in the container, though.

tests/test.sql

@@ -0,0 +1,5 @@
+CREATE TABLE mtftest (id SERIAL NOT NULL, anything VARCHAR(255) NOT NULL);
+
+INSERT INTO mtftest (anything) VALUES ('something');
+
+SELECT anything FROM mtftest;