Note test/install and interactive-debugging tradeoffs for next revisit

Captured per discussion: test/install (cat_tools's pattern) has a real,
independent argument for centralizing fresh/update/existing load-mode
switching in one place, separate from the schema-targeting question. And the
actual debuggability cost of this file's shared/loop-driven design is that
interactively \i-ing a traditional, self-contained test file into psql is
much more direct than poking at this file's generated names and shared
ncs() lookup - not really about automated TAP output specificity, which
mostly localizes failures fine already. Not urgent, not changing now, but
worth revisiting rather than forgetting next time this file is substantially
touched.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Author: jnasbyupgrade

test/core/functions.sql

@@ -1,3 +1,25 @@
+/*
+ * TODO, next time this file is substantially touched - reconsider two
+ * things, not urgent now but worth revisiting rather than forgetting:
+ *
+ * 1. test/install (pgxntool's committed-once installer, see
+ *    Postgres-Extensions/cat_tools's test/install/load.sql): cat_tools uses
+ *    it to centralize its fresh/update/existing load-mode switching in ONE
+ *    place, run once, rather than count_nulls's current test/deps.sql
+ *    (loaded per test file, reinstalling every time). That's a real,
+ *    independent argument for test/install regardless of the schema
+ *    question - count_nulls just hasn't needed to revisit it.
+ *
+ * 2. The debuggability cost of this file's loop-driven, ncs()-indirected
+ *    design isn't really about automated TAP output (which mostly localizes
+ *    failures fine) - it's that a developer can trivially `psql`, `\i` a
+ *    traditional, self-contained test file, and interactively poke at the
+ *    resulting state; doing the same with this file's generated names and
+ *    shared ncs() lookup is much less direct. That's the actual reason
+ *    count_nulls originally had separate, deliberately-independent smoke
+ *    test files (sanity.sql still is one) alongside this shared helper.
+ */
+
 CREATE SCHEMA _null_count_test;
 
 -- See bottom as well!