datalog: magic over rule with aggregate body literal (226/226)

lib/datalog/tests/magic.sx

@@ -197,6 +197,24 @@
         6)
 
       ;; dl-magic-query: end-to-end driver, doesn't mutate caller's db.
+      ;; Magic over a rule whose body contains an aggregate.
+      ;; The rewriter passes aggregate body lits through unchanged
+      ;; (no propagation generated for them), so semi-naive's count
+      ;; logic still fires correctly under the rewritten program.
+      (dl-mt-test! "magic over rule with aggregate body"
+        (let
+          ((db (dl-program
+                 "post(p1). post(p2). post(p3).
+                  liked(u1, p1). liked(u2, p1). liked(u3, p1).
+                  liked(u1, p2).
+                  rich(P) :- post(P), count(N, U, liked(U, P)),
+                             >=(N, 2).")))
+          (let
+            ((semi (dl-query db (list (quote rich) (quote P))))
+              (magic (dl-magic-query db (list (quote rich) (quote P)))))
+            (= (len semi) (len magic))))
+        true)
+
       ;; Mixed EDB + IDB: a relation can be both EDB-seeded and
       ;; rule-derived. dl-magic-query must include the EDB portion
       ;; even though the relation has rules.