diff --git a/.travis.yml b/.travis.yml
index 1a05261..0aa1bbe 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,3 +1,4 @@
+sudo: false
 language: python
 python:
   - "2.6"
@@ -6,9 +7,6 @@ python:
   - "3.3"
   - "3.4"
 
-before_install:
-  - sudo apt-get install portaudio19-dev
-
 install:
   - pip install .
   - pip install coveralls pep8 mock
diff --git a/amodem/audio.py b/amodem/audio.py
index 11804ff..55eb710 100644
--- a/amodem/audio.py
+++ b/amodem/audio.py
@@ -7,11 +7,11 @@ log = logging.getLogger(__name__)
 class Library(object):
     def __init__(self, name):
         self.lib = ctypes.CDLL(name)
-        self.lib.Pa_GetVersionText.restype = ctypes.c_char_p
-        log.debug('Library version: "%s"', self.lib.Pa_GetVersionText())
-        self.lib.Pa_GetErrorText.restype = ctypes.c_char_p
-        assert self.lib.Pa_GetErrorText(0) == 'Success'
         self.streams = []
+        assert self._error_string(0) == 'Success'
+
+    def _error_string(self, code):
+        return self.call('GetErrorText', code, restype=ctypes.c_char_p)
 
     def call(self, name, *args, **kwargs):
         func = getattr(self.lib, 'Pa_{0}'.format(name))
@@ -20,7 +20,7 @@ class Library(object):
 
     def _error_check(self, res):
         if res != 0:
-            raise Exception(res, self.lib.Pa_GetErrorText(res))
+            raise Exception(res, self._error_string(res))
 
     def __enter__(self):
         self.call('Initialize')
diff --git a/tests/test_audio.py b/tests/test_audio.py
index 089f5d9..e072845 100644
--- a/tests/test_audio.py
+++ b/tests/test_audio.py
@@ -1,33 +1,30 @@
 from amodem import audio
-from amodem import config
 
 import mock
+import pytest
 
 
-def test_pyaudio_mock():
-    m = mock.Mock()
-    m.paInt16 = 8
-    m.PyAudio.return_value = m
-    m.open.return_value = m
+def test():
+    length = 1024
+    data = b'\x12\x34' * length
+    with mock.patch('ctypes.CDLL') as cdll:
+        lib = mock.Mock()
+        lib.Pa_GetErrorText = lambda code: 'Error' if code else 'Success'
+        lib.Pa_GetDefaultInputDevice.return_value = 1
+        lib.Pa_OpenStream.return_value = 0
+        cdll.return_value = lib
+        interface = audio.Library('portaudio')
+        with interface:
+            s = interface.player()
+            s.stream = 1  # simulate non-zero output stream handle
+            s.write(data=data)
+            s.close()
 
-    cfg = config.fastest()
-    interface = audio.Interface(config=cfg, library=m)
-    recorder = interface.recorder()
-    n = 1024
-    data = recorder.read(n)
+        with interface:
+            s = interface.recorder()
+            s.stream = 2  # simulate non-zero input stream handle
+            s.read(len(data))
+            s.close()
 
-    data = '\x00' * n
-    player = interface.player()
-    player.write(data)
-
-    kwargs = dict(
-        channels=1, frames_per_buffer=cfg.samples_per_buffer,
-        rate=cfg.Fs, format=m.paInt16
-    )
-    assert m.mock_calls == [
-        mock.call.PyAudio(),
-        mock.call.open(input=True, **kwargs),
-        mock.call.read(n // cfg.sample_size),
-        mock.call.open(output=True, **kwargs),
-        mock.call.write(data)
-    ]
+        with pytest.raises(Exception):
+            interface._error_check(1)