diff --git a/tests/test_context_stream_semantics.py b/tests/test_context_stream_semantics.py
index dda096c..4eb06e8 100644
--- a/tests/test_context_stream_semantics.py
+++ b/tests/test_context_stream_semantics.py
@@ -8,7 +8,9 @@ sync-opening a ``tractor.Context`` beforehand.
 # from contextlib import asynccontextmanager as acm
 from itertools import count
 import platform
-from typing import Optional
+from typing import (
+    Callable,
+)
 
 import pytest
 import trio
@@ -69,7 +71,7 @@ _state: bool = False
 
 @tractor.context
 async def too_many_starteds(
-    ctx: tractor.Context,
+    ctx: Context,
 ) -> None:
     '''
     Call ``Context.started()`` more then once (an error).
@@ -84,7 +86,7 @@ async def too_many_starteds(
 
 @tractor.context
 async def not_started_but_stream_opened(
-    ctx: tractor.Context,
+    ctx: Context,
 ) -> None:
     '''
     Enter ``Context.open_stream()`` without calling ``.started()``.
@@ -105,11 +107,15 @@ async def not_started_but_stream_opened(
     ],
     ids='misuse_type={}'.format,
 )
-def test_started_misuse(target):
-
+def test_started_misuse(
+    target: Callable,
+    debug_mode: bool,
+):
     async def main():
-        async with tractor.open_nursery() as n:
-            portal = await n.start_actor(
+        async with tractor.open_nursery(
+            debug_mode=debug_mode,
+        ) as an:
+            portal = await an.start_actor(
                 target.__name__,
                 enable_modules=[__name__],
             )
@@ -124,7 +130,7 @@ def test_started_misuse(target):
 @tractor.context
 async def simple_setup_teardown(
 
-    ctx: tractor.Context,
+    ctx: Context,
     data: int,
     block_forever: bool = False,
 
@@ -170,6 +176,7 @@ def test_simple_context(
     error_parent,
     callee_blocks_forever,
     pointlessly_open_stream,
+    debug_mode: bool,
 ):
 
     timeout = 1.5 if not platform.system() == 'Windows' else 4
@@ -177,9 +184,10 @@ def test_simple_context(
     async def main():
 
         with trio.fail_after(timeout):
-            async with tractor.open_nursery() as nursery:
-
-                portal = await nursery.start_actor(
+            async with tractor.open_nursery(
+                debug_mode=debug_mode,
+            ) as an:
+                portal = await an.start_actor(
                     'simple_context',
                     enable_modules=[__name__],
                 )
@@ -260,6 +268,7 @@ def test_caller_cancels(
     cancel_method: str,
     chk_ctx_result_before_exit: bool,
     callee_returns_early: bool,
+    debug_mode: bool,
 ):
     '''
     Verify that when the opening side of a context (aka the caller)
@@ -268,7 +277,7 @@ def test_caller_cancels(
 
     '''
     async def check_canceller(
-        ctx: tractor.Context,
+        ctx: Context,
     ) -> None:
         # should not raise yet return the remote
         # context cancelled error.
@@ -287,8 +296,10 @@ def test_caller_cancels(
             )
 
     async def main():
-        async with tractor.open_nursery() as nursery:
-            portal = await nursery.start_actor(
+        async with tractor.open_nursery(
+            debug_mode=debug_mode,
+        ) as an:
+            portal = await an.start_actor(
                 'simple_context',
                 enable_modules=[__name__],
             )
@@ -338,7 +349,7 @@ def test_caller_cancels(
 @tractor.context
 async def close_ctx_immediately(
 
-    ctx: tractor.Context,
+    ctx: Context,
 
 ) -> None:
 
@@ -350,17 +361,33 @@ async def close_ctx_immediately(
 
 
 @tractor_test
-async def test_callee_closes_ctx_after_stream_open():
-    'callee context closes without using stream'
+async def test_callee_closes_ctx_after_stream_open(
+    debug_mode: bool,
+):
+    '''
+    callee context closes without using stream.
 
-    async with tractor.open_nursery() as n:
+    This should result in a msg sequence
+    |_<root>_
+             |_<fast_stream_closer>
 
-        portal = await n.start_actor(
+             <= {'started': <Any>, 'cid': <str>}
+             <= {'stop': True, 'cid': <str>}
+             <= {'result': Any, ..}
+
+     (ignored by child)
+    => {'stop': True, 'cid': <str>}
+
+    '''
+    async with tractor.open_nursery(
+        debug_mode=debug_mode,
+    ) as an:
+        portal = await an.start_actor(
             'fast_stream_closer',
             enable_modules=[__name__],
         )
 
-        with trio.fail_after(2):
+        with trio.fail_after(0.5):
             async with portal.open_context(
                 close_ctx_immediately,
 
@@ -368,10 +395,9 @@ async def test_callee_closes_ctx_after_stream_open():
                 # cancel_on_exit=True,
 
             ) as (ctx, sent):
-
                 assert sent is None
 
-                with trio.fail_after(0.5):
+                with trio.fail_after(0.4):
                     async with ctx.open_stream() as stream:
 
                         # should fall through since ``StopAsyncIteration``
@@ -379,12 +405,15 @@ async def test_callee_closes_ctx_after_stream_open():
                         # a ``trio.EndOfChannel`` by
                         # ``trio.abc.ReceiveChannel.__anext__()``
                         async for _ in stream:
+                            # trigger failure if we DO NOT
+                            # get an EOC!
                             assert 0
                         else:
 
                             # verify stream is now closed
                             try:
-                                await stream.receive()
+                                with trio.fail_after(0.3):
+                                    await stream.receive()
                             except trio.EndOfChannel:
                                 pass
 
@@ -405,7 +434,7 @@ async def test_callee_closes_ctx_after_stream_open():
 @tractor.context
 async def expect_cancelled(
 
-    ctx: tractor.Context,
+    ctx: Context,
 
 ) -> None:
     global _state
@@ -434,11 +463,15 @@ async def expect_cancelled(
 @tractor_test
 async def test_caller_closes_ctx_after_callee_opens_stream(
     use_ctx_cancel_method: bool,
+    debug_mode: bool,
 ):
-    'caller context closes without using stream'
-
-    async with tractor.open_nursery() as an:
+    '''
+    caller context closes without using/opening stream
 
+    '''
+    async with tractor.open_nursery(
+        debug_mode=debug_mode,
+    ) as an:
         root: Actor = current_actor()
 
         portal = await an.start_actor(
@@ -522,11 +555,13 @@ async def test_caller_closes_ctx_after_callee_opens_stream(
 
 
 @tractor_test
-async def test_multitask_caller_cancels_from_nonroot_task():
-
-    async with tractor.open_nursery() as n:
-
-        portal = await n.start_actor(
+async def test_multitask_caller_cancels_from_nonroot_task(
+    debug_mode: bool,
+):
+    async with tractor.open_nursery(
+        debug_mode=debug_mode,
+    ) as an:
+        portal = await an.start_actor(
             'ctx_cancelled',
             enable_modules=[__name__],
         )
@@ -573,7 +608,7 @@ async def test_multitask_caller_cancels_from_nonroot_task():
 @tractor.context
 async def cancel_self(
 
-    ctx: tractor.Context,
+    ctx: Context,
 
 ) -> None:
     global _state
@@ -610,16 +645,20 @@ async def cancel_self(
 
     raise RuntimeError('Context didnt cancel itself?!')
 
+
 @tractor_test
-async def test_callee_cancels_before_started():
+async def test_callee_cancels_before_started(
+    debug_mode: bool,
+):
     '''
     Callee calls `Context.cancel()` while streaming and caller
     sees stream terminated in `ContextCancelled`.
 
     '''
-    async with tractor.open_nursery() as n:
-
-        portal = await n.start_actor(
+    async with tractor.open_nursery(
+        debug_mode=debug_mode,
+    ) as an:
+        portal = await an.start_actor(
             'cancels_self',
             enable_modules=[__name__],
         )
@@ -645,7 +684,7 @@ async def test_callee_cancels_before_started():
 @tractor.context
 async def never_open_stream(
 
-    ctx:  tractor.Context,
+    ctx:  Context,
 
 ) -> None:
     '''
@@ -659,8 +698,8 @@ async def never_open_stream(
 @tractor.context
 async def keep_sending_from_callee(
 
-    ctx:  tractor.Context,
-    msg_buffer_size: Optional[int] = None,
+    ctx:  Context,
+    msg_buffer_size: int|None = None,
 
 ) -> None:
     '''
@@ -685,7 +724,10 @@ async def keep_sending_from_callee(
     ],
     ids='overrun_condition={}'.format,
 )
-def test_one_end_stream_not_opened(overrun_by):
+def test_one_end_stream_not_opened(
+    overrun_by: tuple[str, int, Callable],
+    debug_mode: bool,
+):
     '''
     This should exemplify the bug from:
     https://github.com/goodboy/tractor/issues/265
@@ -696,8 +738,10 @@ def test_one_end_stream_not_opened(overrun_by):
     buf_size = buf_size_increase + Actor.msg_buffer_size
 
     async def main():
-        async with tractor.open_nursery() as n:
-            portal = await n.start_actor(
+        async with tractor.open_nursery(
+            debug_mode=debug_mode,
+        ) as an:
+            portal = await an.start_actor(
                 entrypoint.__name__,
                 enable_modules=[__name__],
             )
@@ -754,7 +798,7 @@ def test_one_end_stream_not_opened(overrun_by):
 @tractor.context
 async def echo_back_sequence(
 
-    ctx:  tractor.Context,
+    ctx:  Context,
     seq: list[int],
     wait_for_cancel: bool,
     allow_overruns_side: str,
@@ -837,6 +881,7 @@ def test_maybe_allow_overruns_stream(
     slow_side: str,
     allow_overruns_side: str,
     loglevel: str,
+    debug_mode: bool,
 ):
     '''
     Demonstrate small overruns of each task back and forth
@@ -855,13 +900,14 @@ def test_maybe_allow_overruns_stream(
 
     '''
     async def main():
-        async with tractor.open_nursery() as n:
-            portal = await n.start_actor(
+        async with tractor.open_nursery(
+            debug_mode=debug_mode,
+        ) as an:
+            portal = await an.start_actor(
                 'callee_sends_forever',
                 enable_modules=[__name__],
                 loglevel=loglevel,
-
-                # debug_mode=True,
+                debug_mode=debug_mode,
             )
             seq = list(range(10))
             async with portal.open_context(
diff --git a/tests/test_inter_peer_cancellation.py b/tests/test_inter_peer_cancellation.py
index 5e1a4ca..1ead617 100644
--- a/tests/test_inter_peer_cancellation.py
+++ b/tests/test_inter_peer_cancellation.py
@@ -123,7 +123,9 @@ async def error_before_started(
                 await peer_ctx.cancel()
 
 
-def test_do_not_swallow_error_before_started_by_remote_contextcancelled():
+def test_do_not_swallow_error_before_started_by_remote_contextcancelled(
+    debug_mode: bool,
+):
     '''
     Verify that an error raised in a remote context which itself
     opens YET ANOTHER remote context, which it then cancels, does not
@@ -132,7 +134,9 @@ def test_do_not_swallow_error_before_started_by_remote_contextcancelled():
 
     '''
     async def main():
-        async with tractor.open_nursery() as n:
+        async with tractor.open_nursery(
+            debug_mode=debug_mode,
+        ) as n:
             portal = await n.start_actor(
                 'errorer',
                 enable_modules=[__name__],
@@ -225,13 +229,16 @@ async def stream_from_peer(
     # NOTE: cancellation of the (sleeper) peer should always
     # cause a `ContextCancelled` raise in this streaming
     # actor.
-    except ContextCancelled as ctxerr:
-        err = ctxerr
+    except ContextCancelled as ctxc:
+        ctxerr = ctxc
+
         assert peer_ctx._remote_error is ctxerr
+        assert peer_ctx._remote_error.msgdata == ctxerr.msgdata
         assert peer_ctx.canceller == ctxerr.canceller
 
         # caller peer should not be the cancel requester
         assert not ctx.cancel_called
+
         # XXX can never be true since `._invoke` only
         # sets this AFTER the nursery block this task
         # was started in, exits.
@@ -269,9 +276,7 @@ async def stream_from_peer(
         # assert ctx.canceller[0] == 'root'
         # assert peer_ctx.canceller[0] == 'sleeper'
 
-    raise RuntimeError(
-        'peer never triggered local `ContextCancelled`?'
-    )
+    raise RuntimeError('Never triggered local `ContextCancelled` ?!?')
 
 
 @pytest.mark.parametrize(
@@ -280,6 +285,7 @@ async def stream_from_peer(
 )
 def test_peer_canceller(
     error_during_ctxerr_handling: bool,
+    debug_mode: bool,
 ):
     '''
     Verify that a cancellation triggered by an in-actor-tree peer
@@ -336,7 +342,7 @@ def test_peer_canceller(
     async def main():
         async with tractor.open_nursery(
             # NOTE: to halt the peer tasks on ctxc, uncomment this.
-            # debug_mode=True
+            debug_mode=debug_mode,
         ) as an:
             canceller: Portal = await an.start_actor(
                 'canceller',
@@ -377,7 +383,8 @@ def test_peer_canceller(
 
                     try:
                         print('PRE CONTEXT RESULT')
-                        await sleeper_ctx.result()
+                        res = await sleeper_ctx.result()
+                        assert res
 
                         # should never get here
                         pytest.fail(
@@ -387,7 +394,10 @@ def test_peer_canceller(
                     # should always raise since this root task does
                     # not request the sleeper cancellation ;)
                     except ContextCancelled as ctxerr:
-                        print(f'CAUGHT REMOTE CONTEXT CANCEL {ctxerr}')
+                        print(
+                            'CAUGHT REMOTE CONTEXT CANCEL FOM\n'
+                            f'{ctxerr}'
+                        )
 
                         # canceller and caller peers should not
                         # have been remotely cancelled.
@@ -410,16 +420,31 @@ def test_peer_canceller(
 
                     # XXX SHOULD NEVER EVER GET HERE XXX
                     except BaseException as berr:
-                        err = berr
-                        pytest.fail('did not rx ctx-cancelled error?')
+                        raise
+
+                        # XXX if needed to debug failure
+                        # _err = berr
+                        # await tractor.pause()
+                        # await trio.sleep_forever()
+
+                        pytest.fail(
+                            'did not rx ctxc ?!?\n\n'
+
+                            f'{berr}\n'
+                        )
+
                     else:
-                        pytest.fail('did not rx ctx-cancelled error?')
+                        pytest.fail(
+                            'did not rx ctxc ?!?\n\n'
+
+                            f'{ctxs}\n'
+                        )
 
             except (
                 ContextCancelled,
                 RuntimeError,
-            )as ctxerr:
-                _err = ctxerr
+            )as loc_err:
+                _loc_err = loc_err
 
                 # NOTE: the main state to check on `Context` is:
                 # - `.cancelled_caught` (maps to nursery cs)
@@ -436,7 +461,7 @@ def test_peer_canceller(
                 # `ContextCancelled` inside `.open_context()`
                 # block
                 if error_during_ctxerr_handling:
-                    assert isinstance(ctxerr, RuntimeError)
+                    assert isinstance(loc_err, RuntimeError)
 
                     # NOTE: this root actor task should have
                     # called `Context.cancel()` on the
@@ -472,9 +497,10 @@ def test_peer_canceller(
 
                 # CASE: standard teardown inside in `.open_context()` block
                 else:
-                    assert ctxerr.canceller == sleeper_ctx.canceller
+                    assert isinstance(loc_err, ContextCancelled)
+                    assert loc_err.canceller == sleeper_ctx.canceller
                     assert (
-                        ctxerr.canceller[0]
+                        loc_err.canceller[0]
                         ==
                         sleeper_ctx.canceller[0]
                         ==
@@ -484,7 +510,7 @@ def test_peer_canceller(
                     # the sleeper's remote error is the error bubbled
                     # out of the context-stack above!
                     re = sleeper_ctx._remote_error
-                    assert re is ctxerr
+                    assert re is loc_err
 
                     for ctx in ctxs:
                         re: BaseException | None = ctx._remote_error
@@ -554,3 +580,14 @@ def test_peer_canceller(
 
         assert excinfo.value.type == ContextCancelled
         assert excinfo.value.canceller[0] == 'canceller'
+
+
+def test_client_tree_spawns_and_cancels_service_subactor():
+    ...
+# TODO: test for the modden `mod wks open piker` bug!
+# -> start actor-tree (server) that offers sub-actor spawns via
+#   context API
+# -> start another full actor-tree (client) which requests to the first to
+#   spawn over its `@context` ep / api.
+# -> client actor cancels the context and should exit gracefully
+#   and the server's spawned child should cancel and terminate!