Adjust debug tests to accomodate no more root clobbering

We may get multiple re-entries to debugger by `bp_forever` sub-actor
now since the root will incrementally try to cancel it only when the tty
lock is not held.

tests/test_debugger.py

@@ -309,32 +309,58 @@ def test_multi_daemon_subactors(spawn, loglevel):
         next_msg = name_error_msg
 
     elif name_error_msg in before:
-        next_msg = None
+        next_msg = bp_forever_msg
 
     else:
         raise ValueError("Neither log msg was found !?")
 
-    child.sendline('c')
+    # NOTE: previously since we did not have clobber prevention
+    # in the root actor this final resume could result in the debugger
+    # tearing down since both child actors would be cancelled and it was
+    # unlikely that `bp_forever` would re-acquire the tty loack again.
+    # Now, we should have a final resumption in the root plus a possible
+    # second entry by `bp_forever`.
 
-    # first name_error failure
+    child.sendline('c')
     child.expect(r"\(Pdb\+\+\)")
     before = str(child.before.decode())
 
-    if next_msg:
-        assert next_msg in before
+    assert next_msg in before
 
-    child.sendline('c')
+    # XXX: hoorayy the root clobering the child here was fixed!
+    # IMO, this demonstrates the true power of SC system design.
 
-    child.expect(r"\(Pdb\+\+\)")
-    before = str(child.before.decode())
-    assert "tractor._exceptions.RemoteActorError: ('name_error'" in before
+    # now the root actor won't clobber the bp_forever child
+    # during it's first access to the debug lock, but will instead
+    # wait for the lock to release, by the edge triggered
+    # ``_debug._no_remote_has_tty`` event before sending cancel messages
+    # (via portals) to its underlings B)
+
+    # at some point here there should have been some warning msg from
+    # the root announcing it avoided a clobber of the child's lock, but
+    # it seems unreliable in testing here to gnab it:
+    # assert "in use by child ('bp_forever'," in before
+
+    # wait for final error in root
+    while True:
+
+        child.sendline('c')
+        child.expect(r"\(Pdb\+\+\)")
+        before = str(child.before.decode())
+        try:
+
+            # root error should be packed as remote error
+            assert "_exceptions.RemoteActorError: ('name_error'" in before
+            break
+
+        except AssertionError:
+            assert bp_forever_msg in before
 
     try:
         child.sendline('c')
         child.expect(pexpect.EOF)
 
     except pexpect.exceptions.TIMEOUT:
-
         # Failed to exit using continue..?
         child.sendline('q')
         child.expect(pexpect.EOF)
@@ -389,7 +415,7 @@ def test_multi_nested_subactors_error_through_nurseries(spawn):
     child = spawn('multi_nested_subactors_error_up_through_nurseries')
 
     # startup time can be iffy
-    time.sleep(1)
+    # time.sleep(1)
 
     for i in range(12):
         try: