diff --git a/appveyor.yml b/appveyor.yml
index 1e010b7..02f9165 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -18,7 +18,7 @@ environment:
     - PYTHON: "C:\\Python36-x64"
 
 matrix:
-  fast_finish: true
+  fast_finish: false
 
 build_script:
   - pip install -e .
diff --git a/fido_host/client.py b/fido_host/client.py
index 1d1ce32..07011e7 100644
--- a/fido_host/client.py
+++ b/fido_host/client.py
@@ -372,6 +372,6 @@ class Fido2Client(object):
                     ),
                     auth_resp.signature
                 )]
-            except ApduError as e:
+            except ApduError:
                 pass  # Ignore this handle
         raise CtapError(CtapError.ERR.NO_CREDENTIALS)
diff --git a/fido_host/pyu2f/macos.py b/fido_host/pyu2f/macos.py
index 9cc05fc..447aaed 100644
--- a/fido_host/pyu2f/macos.py
+++ b/fido_host/pyu2f/macos.py
@@ -111,13 +111,16 @@ K_CF_RUN_LOOP_RUN_STOPPED = 2
 K_CF_RUN_LOOP_RUN_TIMED_OUT = 3
 K_CF_RUN_LOOP_RUN_HANDLED_SOURCE = 4
 
-# Load relevant libraries
-iokit = ctypes.cdll.LoadLibrary(ctypes.util.find_library('IOKit'))
-cf = ctypes.cdll.LoadLibrary(ctypes.util.find_library('CoreFoundation'))
+iokit = None
+cf = None
 
 # Only use iokit and cf if we're on macos, this way we can still run tests
 # on other platforms if we properly mock
 if sys.platform.startswith('darwin'):
+  # Load relevant libraries
+  iokit = ctypes.cdll.LoadLibrary(ctypes.util.find_library('IOKit'))
+  cf = ctypes.cdll.LoadLibrary(ctypes.util.find_library('CoreFoundation'))
+
   # Exported constants
   K_CF_RUNLOOP_DEFAULT_MODE = CF_STRING_REF.in_dll(cf, 'kCFRunLoopDefaultMode')
 
diff --git a/test/test_hid.py b/test/test_hid.py
index 7a3637d..7681ef0 100644
--- a/test/test_hid.py
+++ b/test/test_hid.py
@@ -43,6 +43,6 @@ class HidTest(unittest.TestCase):
         msg2 = b'            '
         msg3 = b''
         dev = self.get_device()
-        self.assertEqual(dev.ping(0x40, 0, 0, msg1), msg1)
-        self.assertEqual(dev.ping(0x40, 0, 0, msg2), msg2)
-        self.assertEqual(dev.ping(0x40, 0, 0, msg3), msg3)
+        self.assertEqual(dev.ping(msg1), msg1)
+        self.assertEqual(dev.ping(msg2), msg2)
+        self.assertEqual(dev.ping(msg3), msg3)