Postgres testing utilities

testutil.sql

-- Raises an exception with `failure_message` if `sql_text` does not throw an exception at all.
-- If an exception is thrown but it's SQLSTATE doesn't match  `expected_sql_state` then that
-- exception is RE-RAISED
CREATE OR REPLACE FUNCTION pg_temp.test__throws_exception(sql_text text, expected_sql_state text, failure_message text) RETURNS void AS $$
DECLARE
   sql_state text;
BEGIN
  EXECUTE sql_text;
  RAISE EXCEPTION '%', failure_message;
  EXCEPTION WHEN OTHERS THEN GET STACKED DIAGNOSTICS sql_state = RETURNED_SQLSTATE;
  IF sql_state = expected_sql_state THEN
    -- Swallow the expected exception
  ELSE
    -- Ensure we RE-RAISE the exception as something else might be wrong such as a syntax error in sql_text
    RAISE;
  END IF;
END;
$$ LANGUAGE plpgsql;