diff --git a/requirements.d/development.txt b/requirements.d/development.txt
new file mode 100644
index 000000000..6d2928a92
--- /dev/null
+++ b/requirements.d/development.txt
@@ -0,0 +1,4 @@
+tox
+mock
+pytest
+Cython
diff --git a/tox.ini b/tox.ini
index 79603cda9..fdf91a2db 100644
--- a/tox.ini
+++ b/tox.ini
@@ -19,9 +19,7 @@ envlist = py32, py33, py34
 # Change dir to avoid import problem for cython code. The directory does
 # not really matter, should be just different from the toplevel dir.
 changedir = {toxworkdir}
-deps =
-    pytest
-    mock
+deps = -rrequirements.d/development.txt
 commands = py.test --pyargs {posargs:borg.testsuite}
 # fakeroot -u needs some env vars:
 passenv = *