add "pragma: no cover" to set_trace() and debug code

we've got some tests to exercise this, so it shouldn't bitrot completely, but
there are some branches-not-taken warnings that I think are spurious

src/wormhole/_allocator.py

@@ -10,7 +10,7 @@ from . import _interfaces
 class Allocator(object):
     _timing = attrib(validator=provides(_interfaces.ITiming))
     m = MethodicalMachine()
-    set_trace = getattr(m, "_setTrace", lambda self, f: None)
+    set_trace = getattr(m, "_setTrace", lambda self, f: None) # pragma: no cover
 
     def wire(self, rendezvous_connector, code):
         self._RC = _interfaces.IRendezvousConnector(rendezvous_connector)

src/wormhole/_boss.py

@@ -37,7 +37,7 @@ class Boss(object):
     _tor = attrib(validator=optional(provides(_interfaces.ITorManager)))
     _timing = attrib(validator=provides(_interfaces.ITiming))
     m = MethodicalMachine()
-    set_trace = getattr(m, "_setTrace", lambda self, f: None)
+    set_trace = getattr(m, "_setTrace", lambda self, f: None) # pragma: no cover
 
     def __attrs_post_init__(self):
         self._build_workers()

src/wormhole/_code.py

@@ -21,7 +21,7 @@ def first(outputs):
 class Code(object):
     _timing = attrib(validator=provides(_interfaces.ITiming))
     m = MethodicalMachine()
-    set_trace = getattr(m, "_setTrace", lambda self, f: None)
+    set_trace = getattr(m, "_setTrace", lambda self, f: None) # pragma: no cover
 
     def wire(self, boss, allocator, nameplate, key, input):
         self._B = _interfaces.IBoss(boss)

src/wormhole/_input.py

@@ -19,7 +19,7 @@ def first(outputs):
 class Input(object):
     _timing = attrib(validator=provides(_interfaces.ITiming))
     m = MethodicalMachine()
-    set_trace = getattr(m, "_setTrace", lambda self, f: None)
+    set_trace = getattr(m, "_setTrace", lambda self, f: None) # pragma: no cover
 
     def __attrs_post_init__(self):
         self._all_nameplates = set()
@@ -30,7 +30,7 @@ class Input(object):
 
     def set_debug(self, f):
         self._trace = f
-    def _debug(self, what):
+    def _debug(self, what): # pragma: no cover
         if self._trace:
             self._trace(old_state="", input=what, new_state="")
 

src/wormhole/_key.py

@@ -64,7 +64,7 @@ class Key(object):
     _side = attrib(validator=instance_of(type(u"")))
     _timing = attrib(validator=provides(_interfaces.ITiming))
     m = MethodicalMachine()
-    set_trace = getattr(m, "_setTrace", lambda self, f: None)
+    set_trace = getattr(m, "_setTrace", lambda self, f: None) # pragma: no cover
 
     def __attrs_post_init__(self):
         self._SK = _SortedKey(self._appid, self._versions, self._side,
@@ -115,7 +115,7 @@ class _SortedKey(object):
     _side = attrib(validator=instance_of(type(u"")))
     _timing = attrib(validator=provides(_interfaces.ITiming))
     m = MethodicalMachine()
-    set_trace = getattr(m, "_setTrace", lambda self, f: None)
+    set_trace = getattr(m, "_setTrace", lambda self, f: None) # pragma: no cover
 
     def wire(self, boss, mailbox, receive):
         self._B = _interfaces.IBoss(boss)

src/wormhole/_lister.py

@@ -10,7 +10,7 @@ from . import _interfaces
 class Lister(object):
     _timing = attrib(validator=provides(_interfaces.ITiming))
     m = MethodicalMachine()
-    set_trace = getattr(m, "_setTrace", lambda self, f: None)
+    set_trace = getattr(m, "_setTrace", lambda self, f: None) # pragma: no cover
 
     def wire(self, rendezvous_connector, input):
         self._RC = _interfaces.IRendezvousConnector(rendezvous_connector)

src/wormhole/_mailbox.py

@@ -10,7 +10,7 @@ from . import _interfaces
 class Mailbox(object):
     _side = attrib(validator=instance_of(type(u"")))
     m = MethodicalMachine()
-    set_trace = getattr(m, "_setTrace", lambda self, f: None)
+    set_trace = getattr(m, "_setTrace", lambda self, f: None) # pragma: no cover
 
     def __attrs_post_init__(self):
         self._mailbox = None

src/wormhole/_nameplate.py

@@ -15,7 +15,7 @@ def validate_nameplate(nameplate):
 @implementer(_interfaces.INameplate)
 class Nameplate(object):
     m = MethodicalMachine()
-    set_trace = getattr(m, "_setTrace", lambda self, f: None)
+    set_trace = getattr(m, "_setTrace", lambda self, f: None) # pragma: no cover
 
     def __init__(self):
         self._nameplate = None

src/wormhole/_order.py

@@ -11,7 +11,7 @@ class Order(object):
     _side = attrib(validator=instance_of(type(u"")))
     _timing = attrib(validator=provides(_interfaces.ITiming))
     m = MethodicalMachine()
-    set_trace = getattr(m, "_setTrace", lambda self, f: None)
+    set_trace = getattr(m, "_setTrace", lambda self, f: None) # pragma: no cover
 
     def __attrs_post_init__(self):
         self._key = None

src/wormhole/_receive.py

@@ -12,7 +12,7 @@ class Receive(object):
     _side = attrib(validator=instance_of(type(u"")))
     _timing = attrib(validator=provides(_interfaces.ITiming))
     m = MethodicalMachine()
-    set_trace = getattr(m, "_setTrace", lambda self, f: None)
+    set_trace = getattr(m, "_setTrace", lambda self, f: None) # pragma: no cover
 
     def __attrs_post_init__(self):
         self._key = None

src/wormhole/_rlcompleter.py

@@ -14,7 +14,7 @@ from .errors import KeyFormatError, AlreadyInputNameplateError
 errf = None
 # uncomment this to enable tab-completion debugging
 #import os ; errf = open("err", "w") if os.path.exists("err") else None
-def debug(*args, **kwargs):
+def debug(*args, **kwargs): # pragma: no cover
     if errf:
         print(*args, file=errf, **kwargs)
         errf.flush()

src/wormhole/_send.py

@@ -12,7 +12,7 @@ class Send(object):
     _side = attrib(validator=instance_of(type(u"")))
     _timing = attrib(validator=provides(_interfaces.ITiming))
     m = MethodicalMachine()
-    set_trace = getattr(m, "_setTrace", lambda self, f: None)
+    set_trace = getattr(m, "_setTrace", lambda self, f: None) # pragma: no cover
 
     def __attrs_post_init__(self):
         self._queue = []

src/wormhole/_terminator.py

@@ -6,7 +6,7 @@ from . import _interfaces
 @implementer(_interfaces.ITerminator)
 class Terminator(object):
     m = MethodicalMachine()
-    set_trace = getattr(m, "_setTrace", lambda self, f: None)
+    set_trace = getattr(m, "_setTrace", lambda self, f: None) # pragma: no cover
 
     def __init__(self):
         self._mood = None
@@ -24,7 +24,7 @@ class Terminator(object):
 
     # TODO: rename o to 0, "" to 1. "S1" is special/terminal
     # so S0nm/S0n/S0m/S0, S1nm/S1n/S1m/(S1)
-    
+
     # We start in Snmo (non-closing). When both nameplate and mailboxes are
     # done, and we're closing, then we stop the RendezvousConnector