diff --git a/lora_comms.py b/lora_comms.py
index 86d09dc..a697c3e 100644
--- a/lora_comms.py
+++ b/lora_comms.py
@@ -62,11 +62,17 @@ def make_pktbuf(s):
 
 process_msgfunc_t = CFUNCTYPE(None, PktBuf, POINTER(PktBuf))
 
-_lib = CDLL('liblora_test.dylib')
-
-_lib._strobe_state_size.restype = c_size_t
-_lib._strobe_state_size.argtypes = ()
-_strobe_state_u64_cnt = (_lib._strobe_state_size() + 7) // 8
+try:
+	_lib = CDLL('liblora_test.dylib')
+except OSError:
+	_lib = None
+
+if _lib is not None:
+	_lib._strobe_state_size.restype = c_size_t
+	_lib._strobe_state_size.argtypes = ()
+	_strobe_state_u64_cnt = (_lib._strobe_state_size() + 7) // 8
+else:
+	_strobe_state_u64_cnt = 1
 
 class CommsSession(Structure,StructureRepr):
 	_fields_ = [
@@ -89,22 +95,23 @@ class CommsState(Structure,StructureRepr):
 		('cs_prevmsgrespbuf', c_uint8 * 64),
 	]
 
-_lib._comms_state_size.restype = c_size_t
-_lib._comms_state_size.argtypes = ()
-
-if _lib._comms_state_size() != sizeof(CommsState): # pragma: no cover
-	raise RuntimeError('CommsState structure size mismatch!')
-
-for func, ret, args in [
-    ('comms_init', None, (POINTER(CommsState), process_msgfunc_t,
-        POINTER(PktBuf))),
-    ('comms_process', None, (POINTER(CommsState), PktBuf, POINTER(PktBuf))),
-    ('strobe_seed_prng', None, (POINTER(c_uint8), c_ssize_t)),
-    ]:
-	f = getattr(_lib, func)
-	f.restype = ret
-	f.argtypes = args
-	locals()[func] = f
+if _lib is not None:
+	_lib._comms_state_size.restype = c_size_t
+	_lib._comms_state_size.argtypes = ()
+
+	if _lib._comms_state_size() != sizeof(CommsState): # pragma: no cover
+		raise RuntimeError('CommsState structure size mismatch!')
+
+	for func, ret, args in [
+	    ('comms_init', None, (POINTER(CommsState), process_msgfunc_t,
+		POINTER(PktBuf))),
+	    ('comms_process', None, (POINTER(CommsState), PktBuf, POINTER(PktBuf))),
+	    ('strobe_seed_prng', None, (POINTER(c_uint8), c_ssize_t)),
+	    ]:
+		f = getattr(_lib, func)
+		f.restype = ret
+		f.argtypes = args
+		locals()[func] = f
 
 def comms_process_wrap(state, input):
 	'''A wrapper around comms_process that converts the argument