fix: isolate immutable session context tests (#714)

tests/test_issue_714_session_context_immutability.py

@@ -6,6 +6,7 @@ import json
 import os
 import sys
 import tempfile
+import threading
 import unittest
 from pathlib import Path
 from unittest.mock import patch
@@ -133,7 +134,6 @@ class TestIssue714SessionContextImmutability(unittest.TestCase):
         mcp_server._IDENTITY_CACHE.clear()
         gitea_config._active_profile_override = None
         mcp_server._MUTATION_AUTHORITY = None
-        session_ctx.clear_session_context()
         self._env = {
             "GITEA_MCP_CONFIG": self.config_path,
             "GITEA_MCP_PROFILE": "mdcps-reviewer",
@@ -147,7 +147,6 @@ class TestIssue714SessionContextImmutability(unittest.TestCase):
         mcp_server._IDENTITY_CACHE.clear()
         gitea_config._active_profile_override = None
         mcp_server._MUTATION_AUTHORITY = None
-        session_ctx.clear_session_context()
         self._dir.cleanup()
 
     def _api_side_effect(self, method, url, header):
@@ -314,7 +313,6 @@ class TestIssue714SessionContextImmutability(unittest.TestCase):
         }
         with patch.dict(os.environ, env, clear=False):
             with patch("mcp_server.api_request", side_effect=self._api_side_effect):
-                session_ctx.clear_session_context()
                 gitea_config._active_profile_override = None
                 res = mcp_server.gitea_resolve_task_capability(
                     task="create_issue", remote="prgs"
@@ -331,7 +329,6 @@ class TestIssue714SessionContextImmutability(unittest.TestCase):
         }
         with patch.dict(os.environ, env, clear=False):
             with patch("mcp_server.api_request", side_effect=self._api_side_effect):
-                session_ctx.clear_session_context()
                 gitea_config._active_profile_override = None
                 res = mcp_server.gitea_resolve_task_capability(
                     task="comment_issue", remote="dadeschools"
@@ -342,12 +339,6 @@ class TestIssue714SessionContextImmutability(unittest.TestCase):
 
 
 class TestSessionContextBindingUnit(unittest.TestCase):
-    def setUp(self):
-        session_ctx.clear_session_context()
-
-    def tearDown(self):
-        session_ctx.clear_session_context()
-
     def test_profile_matches_remote_by_base_url(self):
         remotes = {
             "dadeschools": {"host": "gitea.dadeschools.net"},
@@ -385,6 +376,115 @@ class TestSessionContextBindingUnit(unittest.TestCase):
         self.assertTrue(bad["block"])
         self.assertTrue(any("drift" in r for r in bad["reasons"]))
 
+    def test_bound_context_survives_multiple_calls_and_exceptions(self):
+        original = session_ctx.bind_session_context(
+            profile_name="mdcps-reviewer",
+            remote="dadeschools",
+            host="gitea.dadeschools.net",
+            identity="913443",
+            source="test",
+        )
+
+        try:
+            for _ in range(3):
+                observed = session_ctx.seed_session_context_if_unbound(
+                    profile_name="prgs-author",
+                    remote="prgs",
+                    host="gitea.prgs.cc",
+                    identity="jcwalker3",
+                    source="interleaved-test-call",
+                )
+                self.assertEqual(observed, original)
+            raise RuntimeError("simulated caller failure")
+        except RuntimeError:
+            pass
+
+        self.assertEqual(session_ctx.get_session_context(), original)
+        drift = session_ctx.assess_session_context(
+            profile_name="prgs-author",
+            remote="prgs",
+            host="gitea.prgs.cc",
+            identity="jcwalker3",
+            require_bound=True,
+        )
+        self.assertTrue(drift["block"])
+
+    def test_parallel_calls_cannot_overwrite_established_binding(self):
+        original = session_ctx.bind_session_context(
+            profile_name="mdcps-reviewer",
+            remote="dadeschools",
+            host="gitea.dadeschools.net",
+            identity="913443",
+            source="test",
+        )
+        barrier = threading.Barrier(9)
+        results = []
+        results_lock = threading.Lock()
+
+        def competing_seed(index: int) -> None:
+            barrier.wait()
+            result = session_ctx.seed_session_context_if_unbound(
+                profile_name=f"prgs-author-{index}",
+                remote="prgs",
+                host="gitea.prgs.cc",
+                identity=f"other-{index}",
+                source="parallel-test-call",
+            )
+            with results_lock:
+                results.append(result)
+
+        threads = [threading.Thread(target=competing_seed, args=(i,)) for i in range(8)]
+        for thread in threads:
+            thread.start()
+        barrier.wait()
+        for thread in threads:
+            thread.join(timeout=5)
+
+        self.assertFalse(any(thread.is_alive() for thread in threads))
+        self.assertEqual(results, [original] * 8)
+        self.assertEqual(session_ctx.get_session_context(), original)
+
+    def test_returned_snapshot_cannot_mutate_binding(self):
+        session_ctx.bind_session_context(
+            profile_name="mdcps-reviewer",
+            remote="dadeschools",
+            host="gitea.dadeschools.net",
+            identity="913443",
+            source="test",
+        )
+        snapshot = session_ctx.get_session_context()
+        snapshot["profile_name"] = "prgs-author"
+        self.assertEqual(
+            session_ctx.get_session_context()["profile_name"], "mdcps-reviewer"
+        )
+
+
+class TestSessionContextTestBoundaryIsolation(unittest.TestCase):
+    def test_mdcps_binding_starts_clean_and_does_not_escape_test(self):
+        self.assertIsNone(session_ctx.get_session_context())
+        session_ctx.bind_session_context(
+            profile_name="mdcps-reviewer",
+            remote="dadeschools",
+            host="gitea.dadeschools.net",
+            identity="913443",
+            source="test-boundary",
+        )
+
+    def test_prgs_binding_starts_clean_and_does_not_escape_test(self):
+        self.assertIsNone(session_ctx.get_session_context())
+        session_ctx.bind_session_context(
+            profile_name="prgs-author",
+            remote="prgs",
+            host="gitea.prgs.cc",
+            identity="jcwalker3",
+            source="test-boundary",
+        )
+
+    def test_reset_helper_is_rejected_outside_pytest_boundary(self):
+        with patch.dict(os.environ, {}, clear=True):
+            with self.assertRaises(RuntimeError):
+                session_ctx._reset_session_context_for_testing()
+
 
 if __name__ == "__main__":
     unittest.main()