test: assert failure wiring via AST inside except handlers

Replace the substring-count heuristic in the bot failure-reply wiring
test with AST validation that only counts failure_reply_text(e) calls
inside except handlers, so comments/dead code cannot satisfy the
contract (addresses CodeRabbit review).

Co-authored-by: Mervin Praison <[email protected]>

src/praisonai-bot/tests/unit/bots/test_failure_reply_wiring.py

@@ -1,5 +1,6 @@
 """Regression tests for canonical bot failure rendering."""
 
+import ast
 from pathlib import Path
 
 from praisonaiagents.errors import PraisonAIConfigError
@@ -7,6 +8,30 @@ from praisonaiagents.errors import PraisonAIConfigError
 from praisonai_bot.bots._failure import failure_reply_text
 
 
+def _count_failure_replies_in_handlers(source: str) -> int:
+    """Count ``failure_reply_text(e)`` calls that live inside ``except`` handlers.
+
+    AST-based so that comments, strings, or dead code outside an exception
+    handler cannot satisfy the wiring contract — only genuine terminal
+    failure paths count.
+    """
+    count = 0
+    for handler in ast.walk(ast.parse(source)):
+        if not isinstance(handler, ast.ExceptHandler):
+            continue
+        for node in ast.walk(handler):
+            if (
+                isinstance(node, ast.Call)
+                and isinstance(node.func, ast.Name)
+                and node.func.id == "failure_reply_text"
+                and len(node.args) == 1
+                and isinstance(node.args[0], ast.Name)
+                and node.args[0].id == (handler.name or "e")
+            ):
+                count += 1
+    return count
+
+
 def test_failure_reply_uses_core_taxonomy_and_hides_raw_exception():
     error = PraisonAIConfigError(
         "secret-token-should-not-leak",
@@ -31,7 +56,8 @@ def test_terminal_agent_paths_use_the_canonical_renderer():
 
     for filename, minimum in expected_calls.items():
         source = (bots_dir / filename).read_text(encoding="utf-8")
-        assert source.count("failure_reply_text(e)") >= minimum
+        wired = _count_failure_replies_in_handlers(source)
+        assert wired >= minimum, f"{filename}: {wired} handler calls < {minimum}"
 
 
 def test_retry_paths_do_not_interpolate_raw_exception():