Missing auto-created expected files for .source tests

[jnasbyupgrade]

Problem

pgxntool auto-creates empty test/expected/*.out files for test/sql/*.sql files via a touch rule (base.mk:372-373). But this doesn't cover tests that come from .source files (test/input/*.source).

The .source workflow:

1. User creates test/input/foo.source
2. pg_regress converts it to test/sql/foo.sql at runtime
3. pg_regress needs test/expected/foo.out to diff against

Since test/sql/foo.sql doesn't exist when Make evaluates wildcards, the touch rule never fires for it. pg_regress aborts because it can't find the expected file.

TEST__SOURCE__EXPECTED_FILES (base.mk:64) exists but only covers the case where users also provide test/output/*.source. If a user has test/input/*.source without a corresponding test/output/*.source, the expected file is never created.

Current workaround

The install persistence test manually touches the file:

touch test/expected/pgxntool-test.out

Fix

Add a touch rule for .source-derived expected files:

TEST__SOURCE__RESULT_FILES = $(patsubst $(TESTDIR)/input/%.source,$(TESTDIR)/expected/%.out,$(TEST__SOURCE__INPUT_FILES))
$(TEST__SOURCE__RESULT_FILES): | $(TESTDIR)/expected/
	@touch $@

And add $(TEST__SOURCE__RESULT_FILES) to the installcheck prerequisites.

Ref: https://github.com/Postgres-Extensions/pgxntool-test/pull/7/files#diff-94df59c75ccd1d8edf305cc2d63981f309dfb4c74037a647b83f4e9d4b002ba5R48