diff --git a/tests/conftest.py b/tests/conftest.py
index 674767ff..1a697c1b 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,6 +1,8 @@
 """
-``tractor`` testing!!
+Top level of the testing suites!
+
 """
+from __future__ import annotations
 import sys
 import subprocess
 import os
@@ -30,7 +32,11 @@ else:
     _KILL_SIGNAL = signal.SIGKILL
     _INT_SIGNAL = signal.SIGINT
     _INT_RETURN_CODE = 1 if sys.version_info < (3, 8) else -signal.SIGINT.value
-    _PROC_SPAWN_WAIT = 0.6 if sys.version_info < (3, 7) else 0.4
+    _PROC_SPAWN_WAIT = (
+        0.6
+        if sys.version_info < (3, 7)
+        else 0.4
+    )
 
 
 no_windows = pytest.mark.skipif(
@@ -67,6 +73,15 @@ def pytest_addoption(parser):
         ),
     )
 
+    parser.addoption(
+        "--tpt-proto",
+        action="store",
+        dest='tpt_proto',
+        # default='tcp',  # TODO, mk this default!
+        default='uds',
+        help="Transport protocol to use under the `tractor.ipc.Channel`",
+    )
+
 
 def pytest_configure(config):
     backend = config.option.spawn_backend
@@ -74,7 +89,7 @@ def pytest_configure(config):
 
 
 @pytest.fixture(scope='session')
-def debug_mode(request):
+def debug_mode(request) -> bool:
     debug_mode: bool = request.config.option.tractor_debug_mode
     # if debug_mode:
     #     breakpoint()
@@ -95,6 +110,15 @@ def spawn_backend(request) -> str:
     return request.config.option.spawn_backend
 
 
+@pytest.fixture(scope='session')
+def tpt_proto(request) -> str:
+    proto_key: str = request.config.option.tpt_proto
+    # XXX ensure we support the protocol by name
+    addr_type = tractor._addr._address_types[proto_key]
+    assert addr_type.proto_key == proto_key
+    yield proto_key
+
+
 # @pytest.fixture(scope='function', autouse=True)
 # def debug_enabled(request) -> str:
 #     from tractor import _state
@@ -119,22 +143,38 @@ def ci_env() -> bool:
 #    branch?
 #
 # choose randomly at import time
-_reg_addr: tuple[str, int] = (
-    '127.0.0.1',
-    random.randint(1000, 9999),
-)
+_rando_port: str = random.randint(1000, 9999)
 
 
 @pytest.fixture(scope='session')
-def reg_addr() -> tuple[str, int]:
+def reg_addr(
+    tpt_proto: str,
+) -> tuple[str, int]:
 
     # globally override the runtime to the per-test-session-dynamic
     # addr so that all tests never conflict with any other actor
     # tree using the default.
-    from tractor import _root
-    _root._default_lo_addrs = [_reg_addr]
+    from tractor import (
+        _addr,
+    )
+    tpt_proto: str = _addr.preferred_transport
+    addr_type = _addr._address_types[tpt_proto]
+    def_reg_addr: tuple[str, int] = _addr._default_lo_addrs[tpt_proto]
 
-    return _reg_addr
+    testrun_reg_addr: tuple[str, int]
+    match tpt_proto:
+        case 'tcp':
+            testrun_reg_addr = (
+                addr_type.def_bindspace,
+                _rando_port,
+            )
+        case 'uds':
+            # NOTE, uniqueness will be based on the pid
+            testrun_reg_addr = addr_type.get_random().unwrap()
+            # testrun_reg_addr = def_reg_addr
+
+    assert def_reg_addr != testrun_reg_addr
+    return testrun_reg_addr
 
 
 def pytest_generate_tests(metafunc):
@@ -151,13 +191,25 @@ def pytest_generate_tests(metafunc):
         'trio',
     )
 
-    # NOTE: used to be used to dyanmically parametrize tests for when
+    # NOTE: used-to-be-used-to dyanmically parametrize tests for when
     # you just passed --spawn-backend=`mp` on the cli, but now we expect
     # that cli input to be manually specified, BUT, maybe we'll do
     # something like this again in the future?
     if 'start_method' in metafunc.fixturenames:
-        metafunc.parametrize("start_method", [spawn_backend], scope='module')
+        metafunc.parametrize(
+            "start_method",
+            [spawn_backend],
+            scope='module',
+        )
 
+    # TODO, is this better then parametrizing the fixture above?
+    # spawn_backend = metafunc.config.option.tpt_backend
+    # if 'tpt_proto' in metafunc.fixturenames:
+    #     metafunc.parametrize(
+    #         'tpt_proto',
+    #         [spawn_backend],
+    #         scope='module',
+    #     )
 
 # TODO: a way to let test scripts (like from `examples/`)
 # guarantee they won't registry addr collide!
@@ -171,25 +223,32 @@ def pytest_generate_tests(metafunc):
 #     )
 
 
-def sig_prog(proc, sig):
+def sig_prog(
+    proc: subprocess.Popen,
+    sig: int,
+    canc_timeout: float = 0.1,
+) -> int:
     "Kill the actor-process with ``sig``."
     proc.send_signal(sig)
-    time.sleep(0.1)
+    time.sleep(canc_timeout)
     if not proc.poll():
         # TODO: why sometimes does SIGINT not work on teardown?
         # seems to happen only when trace logging enabled?
         proc.send_signal(_KILL_SIGNAL)
-    ret = proc.wait()
+    ret: int = proc.wait()
     assert ret
 
 
 # TODO: factor into @cm and move to `._testing`?
 @pytest.fixture
 def daemon(
+    debug_mode: bool,
     loglevel: str,
     testdir,
     reg_addr: tuple[str, int],
-):
+    tpt_proto: str,
+
+) -> subprocess.Popen:
     '''
     Run a daemon root actor as a separate actor-process tree and
     "remote registrar" for discovery-protocol related tests.
@@ -200,28 +259,62 @@ def daemon(
         loglevel: str = 'info'
 
     code: str = (
-            "import tractor; "
-            "tractor.run_daemon([], registry_addrs={reg_addrs}, loglevel={ll})"
+        "import tractor; "
+        "tractor.run_daemon([], "
+        "registry_addrs={reg_addrs}, "
+        "debug_mode={debug_mode}, "
+        "loglevel={ll})"
     ).format(
         reg_addrs=str([reg_addr]),
         ll="'{}'".format(loglevel) if loglevel else None,
+        debug_mode=debug_mode,
     )
     cmd: list[str] = [
         sys.executable,
         '-c', code,
     ]
+    # breakpoint()
     kwargs = {}
     if platform.system() == 'Windows':
         # without this, tests hang on windows forever
         kwargs['creationflags'] = subprocess.CREATE_NEW_PROCESS_GROUP
 
-    proc = testdir.popen(
+    proc: subprocess.Popen = testdir.popen(
         cmd,
-        stdout=subprocess.PIPE,
-        stderr=subprocess.PIPE,
         **kwargs,
     )
-    assert not proc.returncode
+
+    # UDS sockets are **really** fast to bind()/listen()/connect()
+    # so it's often required that we delay a bit more starting
+    # the first actor-tree..
+    if tpt_proto == 'uds':
+        _PROC_SPAWN_WAIT: float = 0.6
     time.sleep(_PROC_SPAWN_WAIT)
+
+    assert not proc.returncode
     yield proc
     sig_prog(proc, _INT_SIGNAL)
+
+    # XXX! yeah.. just be reaaal careful with this bc sometimes it
+    # can lock up on the `_io.BufferedReader` and hang..
+    stderr: str = proc.stderr.read().decode()
+    if stderr:
+        print(
+            f'Daemon actor tree produced STDERR:\n'
+            f'{proc.args}\n'
+            f'\n'
+            f'{stderr}\n'
+        )
+    if proc.returncode != -2:
+        raise RuntimeError(
+            'Daemon actor tree failed !?\n'
+            f'{proc.args}\n'
+        )
+
+# @pytest.fixture(autouse=True)
+# def shared_last_failed(pytestconfig):
+#     val = pytestconfig.cache.get("example/value", None)
+#     breakpoint()
+#     if val is None:
+#         pytestconfig.cache.set("example/value", val)
+#     return val
diff --git a/tests/test_discovery.py b/tests/test_discovery.py
index 18b2aa1b..65a76d08 100644
--- a/tests/test_discovery.py
+++ b/tests/test_discovery.py
@@ -7,7 +7,9 @@ import platform
 from functools import partial
 import itertools
 
+import psutil
 import pytest
+import subprocess
 import tractor
 from tractor._testing import tractor_test
 import trio
@@ -152,13 +154,23 @@ async def unpack_reg(actor_or_portal):
 async def spawn_and_check_registry(
     reg_addr: tuple,
     use_signal: bool,
+    debug_mode: bool = False,
     remote_arbiter: bool = False,
     with_streaming: bool = False,
+    maybe_daemon: tuple[
+        subprocess.Popen,
+        psutil.Process,
+    ]|None = None,
 
 ) -> None:
 
+    if maybe_daemon:
+        popen, proc = maybe_daemon
+        # breakpoint()
+
     async with tractor.open_root_actor(
         registry_addrs=[reg_addr],
+        debug_mode=debug_mode,
     ):
         async with tractor.get_registry(reg_addr) as portal:
             # runtime needs to be up to call this
@@ -176,11 +188,11 @@ async def spawn_and_check_registry(
                 extra = 2  # local root actor + remote arbiter
 
             # ensure current actor is registered
-            registry = await get_reg()
+            registry: dict = await get_reg()
             assert actor.uid in registry
 
             try:
-                async with tractor.open_nursery() as n:
+                async with tractor.open_nursery() as an:
                     async with trio.open_nursery(
                         strict_exception_groups=False,
                     ) as trion:
@@ -189,17 +201,17 @@ async def spawn_and_check_registry(
                         for i in range(3):
                             name = f'a{i}'
                             if with_streaming:
-                                portals[name] = await n.start_actor(
+                                portals[name] = await an.start_actor(
                                     name=name, enable_modules=[__name__])
 
                             else:  # no streaming
-                                portals[name] = await n.run_in_actor(
+                                portals[name] = await an.run_in_actor(
                                     trio.sleep_forever, name=name)
 
                         # wait on last actor to come up
                         async with tractor.wait_for_actor(name):
                             registry = await get_reg()
-                            for uid in n._children:
+                            for uid in an._children:
                                 assert uid in registry
 
                         assert len(portals) + extra == len(registry)
@@ -232,6 +244,7 @@ async def spawn_and_check_registry(
 @pytest.mark.parametrize('use_signal', [False, True])
 @pytest.mark.parametrize('with_streaming', [False, True])
 def test_subactors_unregister_on_cancel(
+    debug_mode: bool,
     start_method,
     use_signal,
     reg_addr,
@@ -248,6 +261,7 @@ def test_subactors_unregister_on_cancel(
                 spawn_and_check_registry,
                 reg_addr,
                 use_signal,
+                debug_mode=debug_mode,
                 remote_arbiter=False,
                 with_streaming=with_streaming,
             ),
@@ -257,7 +271,8 @@ def test_subactors_unregister_on_cancel(
 @pytest.mark.parametrize('use_signal', [False, True])
 @pytest.mark.parametrize('with_streaming', [False, True])
 def test_subactors_unregister_on_cancel_remote_daemon(
-    daemon,
+    daemon: subprocess.Popen,
+    debug_mode: bool,
     start_method,
     use_signal,
     reg_addr,
@@ -273,8 +288,13 @@ def test_subactors_unregister_on_cancel_remote_daemon(
                 spawn_and_check_registry,
                 reg_addr,
                 use_signal,
+                debug_mode=debug_mode,
                 remote_arbiter=True,
                 with_streaming=with_streaming,
+                maybe_daemon=(
+                    daemon,
+                    psutil.Process(daemon.pid)
+                ),
             ),
         )
 
@@ -373,7 +393,7 @@ def test_close_channel_explicit(
 
 @pytest.mark.parametrize('use_signal', [False, True])
 def test_close_channel_explicit_remote_arbiter(
-    daemon,
+    daemon: subprocess.Popen,
     start_method,
     use_signal,
     reg_addr,