fix multi-session results placed in separate timestamp directories

Documentation/multi-session.rst

@@ -101,8 +101,9 @@ fails the entire run is aborted immediately.
 Phase 2: Test
 -------------
 
-After all builds succeed, test sessions are executed.  Each session gets its
-own sub-directory under a single timestamped result directory
+After all builds succeed, a single timestamped result directory is created
+(e.g. ``result/2026-04-14_18-30-00/``).  Each session writes its results
+into a sub-directory named after the session
 (``result/<timestamp>/<session-name>/``).
 
 In **sequential mode** (default) sessions run in manifest order.  With
@@ -121,13 +122,31 @@ Phase 3: Report
 ---------------
 
 Individual session JUnit XML reports are merged into a single
-``report.xml`` at the master result directory.  Testsuite names and
+``report.xml`` in the shared result directory.  Testsuite names and
 testcase classnames are prefixed with the session name
 (``<session>::<original>``), so results from different sessions never
 collide.
 
 A unified HTML summary is generated from the merged report.
 
+The final directory layout looks like this::
+
+  result/<timestamp>/
+      report.xml                           # merged JUnit XML
+      report/
+          result_summary.txt               # aggregated summary
+          result_summary.html
+      session-a/
+          report.xml                       # session-a JUnit XML
+          report.html
+          session.config.txt
+          ...
+      session-b/
+          report.xml
+          report.html
+          session.config.txt
+          ...
+
 Resource Tags
 =============
 

src/ntfc/multi.py

@@ -263,10 +263,15 @@ def run(self) -> int:
         if built_configs is None:
             return 1
 
+        # Create shared session directory for all sessions
+        log_manager = LogManager(self._logcfg)
+        log_manager.cleanup()
+        self._session_dir = log_manager.new_session_dir()
+
         # Phase 2: Run all test sessions
         results = self._phase_test(built_configs)
 
-        # Phase 3: Merge reports
+        # Phase 3: Merge reports into the shared session directory
         self._phase_report(results)
 
         # Print final summary
@@ -519,7 +524,11 @@ def _run_session(
         pt = MyPytest(conf, exitonfail, self._verbose, modules=modules)
 
         logger.info(f"[Multi] Running session '{session.name}'")
-        result: Dict[str, Any] = {"logcfg": self._logcfg}
+        session_result_dir = os.path.join(self._session_dir, session.name)
+        result: Dict[str, Any] = {
+            "logcfg": self._logcfg,
+            "result_dir": session_result_dir,
+        }
         exit_code = pt.runner(session.testpath, result)
 
         # read result_dir from the instance, not global pytest module
@@ -621,11 +630,8 @@ def _phase_report(self, results: List["SessionResult"]) -> None:
         """
         logger.info("[Multi] Phase 3: Merging reports")
 
-        log_manager = LogManager(self._logcfg)
-        merge_dir = log_manager.new_session_dir()
-
         reporter = Reporter()
-        self._merge_session_reports(merge_dir, results, reporter)
+        self._merge_session_reports(self._session_dir, results, reporter)
 
     @staticmethod
     def _copy_testcase(

src/ntfc/pytest/mypytest.py

@@ -338,10 +338,15 @@ def runner(
             opt.append(testpath)
 
         if not nologs:  # pragma: no cover
-            # create result directory via LogManager
-            log_manager = LogManager(result.get("logcfg"))
-            log_manager.cleanup()
-            pytest.result_dir = log_manager.new_session_dir()
+            if "result_dir" in result:
+                # Use pre-created result directory (multi-session mode)
+                pytest.result_dir = result["result_dir"]
+                os.makedirs(pytest.result_dir, exist_ok=True)
+            else:
+                # create result directory via LogManager
+                log_manager = LogManager(result.get("logcfg"))
+                log_manager.cleanup()
+                pytest.result_dir = log_manager.new_session_dir()
             self.result_dir = pytest.result_dir
             self._write_session_config(pytest.result_dir)
 

tests/test_multi.py

@@ -394,10 +394,14 @@ def test_run_all_pass(tmp_path):
     )
     runner = _make_runner(mc)
 
+    mock_log_mgr = MagicMock()
+    mock_log_mgr.new_session_dir.return_value = tmp
+
     with (
         patch.object(runner, "_phase_build") as mock_build,
         patch.object(runner, "_phase_test") as mock_test,
         patch.object(runner, "_phase_report"),
+        patch("ntfc.multi.LogManager", return_value=mock_log_mgr),
     ):
         mock_build.return_value = {"s1": {}, "s2": {}}
         mock_test.return_value = [
@@ -417,10 +421,14 @@ def test_run_session_fails(tmp_path):
     )
     runner = _make_runner(mc)
 
+    mock_log_mgr = MagicMock()
+    mock_log_mgr.new_session_dir.return_value = tmp
+
     with (
         patch.object(runner, "_phase_build") as mock_build,
         patch.object(runner, "_phase_test") as mock_test,
         patch.object(runner, "_phase_report"),
+        patch("ntfc.multi.LogManager", return_value=mock_log_mgr),
     ):
         mock_build.return_value = {"s1": {}}
         mock_test.return_value = [
@@ -751,6 +759,7 @@ def test_run_session_calls_mypytest(tmp_path):
         ],
     )
     runner = MultiSessionRunner(mc, rebuild=False)
+    runner._session_dir = tmp
 
     mock_pt = MagicMock()
     mock_pt.runner.return_value = 0
@@ -763,6 +772,11 @@ def test_run_session_calls_mypytest(tmp_path):
     assert result.result_dir == "/tmp/fake_result"
     mock_pt.runner.assert_called_once()
 
+    # Verify result_dir was passed to runner
+    call_args = mock_pt.runner.call_args
+    result_dict = call_args[0][1]
+    assert result_dict["result_dir"] == os.path.join(tmp, "s1")
+
 
 def test_run_session_sets_fail_event(tmp_path):
     tmp = str(tmp_path)
@@ -773,6 +787,7 @@ def test_run_session_sets_fail_event(tmp_path):
         sessions=[SessionConfig(name="s1", confpath=confpath, testpath=tmp)],
     )
     runner = MultiSessionRunner(mc, rebuild=False)
+    runner._session_dir = tmp
 
     fail_event = threading.Event()
 
@@ -847,14 +862,11 @@ def test_phase_report(tmp_path):
         sessions=[SessionConfig(name="s1", confpath=confpath, testpath=tmp)],
     )
     runner = MultiSessionRunner(mc, rebuild=False)
+    runner._session_dir = tmp
 
     results = [SessionResult("s1", 0, tmp)]
 
-    mock_log_mgr = MagicMock()
-    mock_log_mgr.new_session_dir.return_value = tmp
-
     with (
-        patch("ntfc.multi.LogManager", return_value=mock_log_mgr),
         patch("ntfc.multi.Reporter") as mock_rep_cls,
         patch.object(
             MultiSessionRunner, "_merge_session_reports"