migrate session handling to aioweb_tls/refactoring of helpers

tests/test_pagination_semaphore.py

@@ -1,11 +1,12 @@
 """unit test: execute_pagination honours a caller-supplied shared semaphore
 
 run from the repo root:
-    uv run python tests/test_pagination_semaphore.py
+    uv run pytest tests/test_pagination_semaphore.py
 
 offline — no network. A fake page func records peak concurrency so we can
 assert the fan-out limit actually holds, both for the shared-semaphore path
-(one instance capping many categories at once) and the default per-call path.
+(one instance capping many categories at once) and a single call bounding one
+category with its own semaphore.
 """
 
 import asyncio
@@ -62,9 +63,10 @@ def test_shared_semaphore_caps_total_concurrency_across_categories():
     assert state["peak"] <= limit, f"peak {state['peak']} exceeded shared limit {limit}"
 
 
-def test_default_falls_back_to_max_concurrent_tasks():
-    """Without a semaphore, max_concurrent_tasks still bounds a single call."""
+def test_single_call_respects_its_semaphore():
+    """A single call bounds its own fan-out to the supplied semaphore limit."""
 
+    limit = 2
     state = {"live": 0, "peak": 0}
     func = _make_tracking_func(state)
 
@@ -75,13 +77,8 @@ def test_default_falls_back_to_max_concurrent_tasks():
             products_per_page=30,
             func=func,
             session=None,
-            max_concurrent_tasks=2,
+            semaphore=asyncio.Semaphore(limit),
         )
 
     asyncio.run(run())
-    assert state["peak"] <= 2, f"peak {state['peak']} exceeded max_concurrent_tasks 2"
-
-
-test_shared_semaphore_caps_total_concurrency_across_categories()
-test_default_falls_back_to_max_concurrent_tasks()
-print("pagination semaphore test passed")
+    assert state["peak"] <= limit, f"peak {state['peak']} over limit {limit}"