Since the plpgsql test has been part of the standard regression tests

src/pl/plpgsql/test/README

src/pl/plpgsql/test/expected/tables.out

src/pl/plpgsql/test/expected/test.out

src/pl/plpgsql/test/expected/triggers.out

src/pl/plpgsql/test/expected/views.out

src/pl/plpgsql/test/runtest

src/pl/plpgsql/test/tables.sql

src/pl/plpgsql/test/test.sql

src/pl/plpgsql/test/triggers.sql

src/pl/plpgsql/test/views.sql