commerce: time-windowed promotions (19 tests) — Phase 5 ext

window.sx — a validity window kept separate from the promo tuple (promo.sx
untouched): windowed promo (promo from until), inclusive int timestamps, nil =
open bound. active-ruleset filters to promos live at `at` and feeds the existing
promo/stack/quote pipeline; active-codes is the backward "which codes live at
T?" query; windowed-quote is the datetime-aware, deterministic quote.
Total 228/228 across 14 suites.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/commerce/tests/window.sx

@@ -0,0 +1,112 @@
+;; lib/commerce/tests/window.sx — time-windowed promotions.
+;; Uses (commerce-test name got expected) provided by conformance.sh.
+
+(define
+  pcat
+  (make-catalog (list (list "widget" 1000 :standard)) (list) (list)))
+
+(define gctx (make-pricing-context pcat (list) :uk :guest))
+(define cart (list (list "widget" :none 3)))
+
+(define ten (list :percent "TEN" :standard 1000))
+(define twenty (list :percent "TWENTY" :standard 2000))
+(define always (list :fixed "ALWAYS" 0 100))
+
+(define
+  windowed
+  (list
+    (windowed-promo ten 100 200)
+    (windowed-promo twenty 150 300)
+    (windowed-promo always nil nil)))
+
+(define exclusions (list (list "TEN" "TWENTY")))
+
+;; --- wp-active? boundaries (inclusive) ---
+
+(commerce-test
+  "active-at-from"
+  (wp-active? (windowed-promo ten 100 200) 100)
+  true)
+(commerce-test
+  "active-at-until"
+  (wp-active? (windowed-promo ten 100 200) 200)
+  true)
+(commerce-test
+  "inactive-before"
+  (wp-active? (windowed-promo ten 100 200) 99)
+  false)
+(commerce-test
+  "inactive-after"
+  (wp-active? (windowed-promo ten 100 200) 201)
+  false)
+(commerce-test
+  "open-ended-always"
+  (wp-active? (windowed-promo always nil nil) 99999)
+  true)
+(commerce-test
+  "open-lower"
+  (wp-active? (windowed-promo ten nil 200) 1)
+  true)
+(commerce-test
+  "open-upper"
+  (wp-active? (windowed-promo ten 100 nil) 99999)
+  true)
+
+;; --- active-ruleset filtering ---
+
+(commerce-test
+  "active-ruleset-120"
+  (active-ruleset windowed 120)
+  (list ten always))
+(commerce-test
+  "active-ruleset-160"
+  (active-ruleset windowed 160)
+  (list ten twenty always))
+(commerce-test
+  "active-ruleset-250"
+  (active-ruleset windowed 250)
+  (list twenty always))
+(commerce-test
+  "active-ruleset-50"
+  (active-ruleset windowed 50)
+  (list always))
+
+;; --- active-codes (backward query) ---
+
+(commerce-test
+  "active-codes-120"
+  (active-codes windowed 120)
+  (list "TEN" "ALWAYS"))
+(commerce-test
+  "active-codes-160"
+  (active-codes windowed 160)
+  (list "TEN" "TWENTY" "ALWAYS"))
+(commerce-test
+  "active-codes-50"
+  (active-codes windowed 50)
+  (list "ALWAYS"))
+
+;; --- windowed-quote: discount changes with time (deterministic) ---
+;; subtotal 3000, no tax. TEN=300, TWENTY=600, ALWAYS=100; TEN/TWENTY exclusive.
+
+(commerce-test
+  "quote-50"
+  (quote-discount (windowed-quote gctx cart windowed exclusions 50))
+  100)
+(commerce-test
+  "quote-120"
+  (quote-discount (windowed-quote gctx cart windowed exclusions 120))
+  400)
+(commerce-test
+  "quote-160"
+  (quote-discount (windowed-quote gctx cart windowed exclusions 160))
+  700)
+(commerce-test
+  "quote-250"
+  (quote-discount (windowed-quote gctx cart windowed exclusions 250))
+  700)
+
+(commerce-test
+  "quote-total-160"
+  (quote-total (windowed-quote gctx cart windowed exclusions 160))
+  2300)