diff --git a/secret_handshake/util.py b/secret_handshake/util.py
index c5e0053..d13f99f 100644
--- a/secret_handshake/util.py
+++ b/secret_handshake/util.py
@@ -20,36 +20,11 @@
 
 
 import struct
-from io import BytesIO
 
 NONCE_SIZE = 24
 MAX_NONCE = 8 * NONCE_SIZE
 
 
-class AsyncBuffer(BytesIO):
-    """Just a BytesIO with an async read method."""
-
-    async def read(self, n=None):
-        v = super(AsyncBuffer, self).read(n)
-        return v
-
-    readexactly = read
-
-    def append(self, data):
-        """Append data to the buffer without changing the current position."""
-        pos = self.tell()
-        self.write(data)
-        self.seek(pos)
-
-
-async def async_comprehend(generator):
-    """Emulate ``[elem async for elem in generator]``."""
-    results = []
-    async for msg in generator:
-        results.append(msg)
-    return results
-
-
 def inc_nonce(nonce):
     num = bytes_to_long(nonce) + 1
     if num > 2**MAX_NONCE:
diff --git a/tests/helpers.py b/tests/helpers.py
new file mode 100644
index 0000000..5f0420b
--- /dev/null
+++ b/tests/helpers.py
@@ -0,0 +1,47 @@
+# Copyright (c) 2017 PySecretHandshake contributors (see AUTHORS for more details)
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+"""Helper utilities for testing"""
+
+from io import BytesIO
+
+
+class AsyncBuffer(BytesIO):
+    """Just a BytesIO with an async read method."""
+
+    async def read(self, n=None):
+        v = super(AsyncBuffer, self).read(n)
+        return v
+
+    readexactly = read
+
+    def append(self, data):
+        """Append data to the buffer without changing the current position."""
+        pos = self.tell()
+        self.write(data)
+        self.seek(pos)
+
+
+async def async_comprehend(generator):
+    """Emulate ``[elem async for elem in generator]``."""
+    results = []
+    async for msg in generator:
+        results.append(msg)
+    return results
diff --git a/tests/test_boxstream.py b/tests/test_boxstream.py
index 395d222..6605995 100644
--- a/tests/test_boxstream.py
+++ b/tests/test_boxstream.py
@@ -22,8 +22,8 @@
 import pytest
 
 from secret_handshake.boxstream import HEADER_LENGTH, BoxStream, UnboxStream
-from secret_handshake.util import AsyncBuffer, async_comprehend
 
+from .helpers import AsyncBuffer, async_comprehend
 from .test_crypto import CLIENT_ENCRYPT_KEY, CLIENT_ENCRYPT_NONCE
 
 MESSAGE_1 = (
diff --git a/tests/test_network.py b/tests/test_network.py
index bece634..b5bf94b 100644
--- a/tests/test_network.py
+++ b/tests/test_network.py
@@ -24,7 +24,7 @@ from asyncio import Event, wait_for
 import pytest
 from nacl.signing import SigningKey
 
-from secret_handshake.util import AsyncBuffer
+from .helpers import AsyncBuffer
 
 
 class DummyCrypto(object):