identity: session-as-process — create/lookup/expire/revoke + idle timeout (11 tests)

Session is an Erlang process holding {subject, client, status}. lookup/
touch/expire/revoke are messages; expiry is the process's own
`receive ... after Ttl` timeout (RFC-agnostic; no global sweep), which
notifies the owner and tombstones. Tombstoned sessions answer lookups
with an explicit {error, expired|revoked}, never a silent dead mailbox.
Adds the conformance harness + scoreboard.

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

lib/identity/tests/session.sx

@@ -0,0 +1,118 @@
+;; identity/tests/session.sx — session-as-process: create, lookup,
+;; touch, explicit expire, revoke, and idle-timeout self-expiry.
+;; Negative paths are tested as first-class: a tombstoned session
+;; answers {error, Status}, it does not go silent.
+
+(define id-session-test-count 0)
+(define id-session-test-pass 0)
+(define id-session-test-fails (list))
+
+(define
+  id-session-test
+  (fn
+    (name actual expected)
+    (set! id-session-test-count (+ id-session-test-count 1))
+    (if
+      (= actual expected)
+      (set! id-session-test-pass (+ id-session-test-pass 1))
+      (append! id-session-test-fails {:name name :expected expected :actual actual}))))
+
+(define id-ev erlang-eval-ast)
+(define idnm (fn (v) (get v :name)))
+
+(identity-load-session!)
+
+;; ── create + lookup ──────────────────────────────────────────────
+
+(id-session-test
+  "lookup of live session is active"
+  (idnm
+    (id-ev
+      "Me = self(),\n       S = identity_session:start(s1, alice, web, Me, infinity),\n       case identity_session:lookup(S) of {ok, {_,_,_,St}} -> St end"))
+  "active")
+
+(id-session-test
+  "lookup preserves subject"
+  (idnm
+    (id-ev
+      "Me = self(),\n       S = identity_session:start(s1, alice, web, Me, infinity),\n       case identity_session:lookup(S) of {ok, {_,Subject,_,_}} -> Subject end"))
+  "alice")
+
+(id-session-test
+  "lookup preserves client"
+  (idnm
+    (id-ev
+      "Me = self(),\n       S = identity_session:start(s1, alice, web, Me, infinity),\n       case identity_session:lookup(S) of {ok, {_,_,Client,_}} -> Client end"))
+  "web")
+
+;; ── touch keeps a live session ───────────────────────────────────
+
+(id-session-test
+  "touch on live session is ok"
+  (idnm
+    (id-ev
+      "Me = self(),\n       S = identity_session:start(s1, alice, web, Me, infinity),\n       identity_session:touch(S)"))
+  "ok")
+
+;; ── explicit expire ──────────────────────────────────────────────
+
+(id-session-test
+  "expire then lookup is error expired"
+  (idnm
+    (id-ev
+      "Me = self(),\n       S = identity_session:start(s1, alice, web, Me, infinity),\n       identity_session:expire(S),\n       case identity_session:lookup(S) of {error, St} -> St end"))
+  "expired")
+
+(id-session-test
+  "touch on expired session is error"
+  (idnm
+    (id-ev
+      "Me = self(),\n       S = identity_session:start(s1, alice, web, Me, infinity),\n       identity_session:expire(S),\n       case identity_session:touch(S) of {error, St} -> St end"))
+  "expired")
+
+;; ── revoke is immediate ──────────────────────────────────────────
+
+(id-session-test
+  "revoke then lookup is error revoked"
+  (idnm
+    (id-ev
+      "Me = self(),\n       S = identity_session:start(s1, alice, web, Me, infinity),\n       identity_session:revoke(S),\n       case identity_session:lookup(S) of {error, St} -> St end"))
+  "revoked")
+
+;; ── idle-timeout self-expiry ─────────────────────────────────────
+
+(id-session-test
+  "idle timeout notifies owner"
+  (idnm
+    (id-ev
+      "Me = self(),\n       S = identity_session:start(s1, alice, web, Me, 50),\n       _ = identity_session:lookup(S),\n       receive {session_expired, Sid} -> Sid end"))
+  "s1")
+
+(id-session-test
+  "lookup after idle timeout is error expired"
+  (idnm
+    (id-ev
+      "Me = self(),\n       S = identity_session:start(s1, alice, web, Me, 50),\n       _ = identity_session:lookup(S),\n       receive {session_expired, _} -> ok end,\n       case identity_session:lookup(S) of {error, St} -> St end"))
+  "expired")
+
+;; ── isolation: sessions are independent processes ────────────────
+
+(id-session-test
+  "expiring one session leaves the other active"
+  (idnm
+    (id-ev
+      "Me = self(),\n       A = identity_session:start(s1, alice, web, Me, infinity),\n       B = identity_session:start(s2, bob, web, Me, infinity),\n       identity_session:expire(A),\n       case identity_session:lookup(B) of {ok, {_,_,_,St}} -> St end"))
+  "active")
+
+;; ── clean stop ───────────────────────────────────────────────────
+
+(id-session-test
+  "stop returns ok"
+  (idnm
+    (id-ev
+      "Me = self(),\n       S = identity_session:start(s1, alice, web, Me, infinity),\n       identity_session:stop(S)"))
+  "ok")
+
+(define
+  id-session-test-summary
+  (str "session " id-session-test-pass "/" id-session-test-count))