content: tree-wide block transforms (transform.sx) + 12 tests (586/586)

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

lib/content/tests/transform.sx

@@ -0,0 +1,90 @@
+;; Extension — tree-wide block transforms.
+
+(st-bootstrap-classes!)
+(content/bootstrap!)
+(content-bootstrap-section!)
+
+(define
+  d
+  (doc-append
+    (doc-append (doc-empty "d") (mk-heading "h" 1 "Top"))
+    (mk-section
+      "s"
+      (list (mk-text "a" "A") (mk-heading "h2" 2 "Sub")))))
+
+;; ── map-type bumps heading levels everywhere ──
+(define
+  d1
+  (content/map-type
+    d
+    "heading"
+    (fn (b) (blk-set b "level" (+ (blk-get b "level") 1)))))
+(content-test
+  "map-type top heading"
+  (blk-send (doc-deep-find d1 "h") "level")
+  2)
+(content-test
+  "map-type nested heading"
+  (blk-send (doc-deep-find d1 "h2") "level")
+  3)
+(content-test
+  "map-type leaves text"
+  (str (blk-send (doc-deep-find d1 "a") "text"))
+  "A")
+(content-test
+  "map-type immutable"
+  (blk-send (doc-deep-find d "h") "level")
+  1)
+(content-test "map-type preserves tree" (doc-tree-ids d1) (doc-tree-ids d))
+
+;; ── set-field-on rewrites all text blocks ──
+(define d2 (content/set-field-on d "text" "text" "REDACTED"))
+(content-test
+  "set-field nested text"
+  (str (blk-send (doc-deep-find d2 "a") "text"))
+  "REDACTED")
+(content-test
+  "set-field count"
+  (len
+    (filter
+      (fn (b) (= (str (blk-get b "text")) "REDACTED"))
+      (list (doc-deep-find d2 "a"))))
+  1)
+
+;; ── map-blocks with custom predicate ──
+(define
+  d3
+  (content/map-blocks
+    d
+    (fn (b) (= (blk-id b) "h2"))
+    (fn (b) (blk-set b "text" "Changed"))))
+(content-test
+  "map-blocks predicate hit"
+  (str (blk-send (doc-deep-find d3 "h2") "text"))
+  "Changed")
+(content-test
+  "map-blocks predicate miss"
+  (str (blk-send (doc-deep-find d3 "h") "text"))
+  "Top")
+
+;; ── image src rewrite (cdn migration) ──
+(define di (doc-append (doc-empty "d") (mk-image "img" "/old.png" "x")))
+(content-test
+  "image src rewrite"
+  (str
+    (blk-send
+      (doc-find (content/set-field-on di "image" "src" "/cdn/new.png") "img")
+      "src"))
+  "/cdn/new.png")
+
+;; ── no matching blocks → unchanged ──
+(content-test
+  "no match unchanged"
+  (asHTML (content/map-type d "embed" (fn (b) b)))
+  (asHTML d))
+
+;; ── render after transform ──
+(content-test
+  "render after map-type"
+  (asHTML d1)
+  "<h2>Top</h2><section><p>A</p><h3>Sub</h3></section>")