diff --git a/.travis.yml b/.travis.yml
index 65bb0d9..978a025 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,21 +3,24 @@ language: python
 matrix:
     include:
       - python: 2.7
-        env: TOX_ENV=py27
+        env: TOX_ENV=py27 DOCOV=false
       - python: 3.5
-        env: TOX_ENV=py35
+        env: TOX_ENV=py35 DOCOV=true
       - python: 3.6
-        env: TOX_ENV=py36
+        env: TOX_ENV=py36 DOCOV=false
       - python: pypy
-        env: TOX_ENV=pypy
+        env: TOX_ENV=pypy DOCOV=false
       - python: 3.6
-        env: TOX_ENV=flake8
+        env: TOX_ENV=flake8 DOCOV=false
 
-install: pip install -U tox-travis funcsigs coveralls pytest
+install: 
+  - pip uninstall -y funcsigs || true
+  - pip install -U tox-travis coveralls pytest
+  - pip install -r requirements_dev.txt
 
 script: 
   - tox -e $TOX_ENV
-  - coverage run --source modpipe -m py.test
+  - ($DOCOV && ccoverage run --source modpipe -m py.test) || true
 
 after_success: coveralls
 
diff --git a/appveyor.yml b/appveyor.yml
index 87e4d6a..e98e8ec 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -12,7 +12,8 @@ environment:
 
 install:
   - "%PYTHON%/Scripts/easy_install -U pip"
-  - "%PYTHON%/Scripts/pip install tox wheel funcsigs"
+  - "%PYTHON%/Scripts/pip install tox wheel"
+  - "%PYTHON%/Scripts/pip install --force-reinstall -r requirements_dev.txt"
 
 build: false  # Not a C# project, build stuff at the test step instead.
 
diff --git a/requirements_dev.txt b/requirements_dev.txt
index 1ba26e1..549821e 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -10,3 +10,4 @@ twine==1.10.0
 
 pytest==3.4.2
 pytest-runner==2.11.1
+git+git://github.com/jbn/funcsigs.git@214840c53529f019638229d72dcf2257fe154458#egg=funcsigs
diff --git a/tox.ini b/tox.ini
index 48007bc..fc13866 100644
--- a/tox.ini
+++ b/tox.ini
@@ -2,8 +2,7 @@
 envlist = py27,py35,py36,pypy,flake8
 
 [testenv]
-deps = 
-    pytest>=3.0
+deps = -rrequirements_dev.txt
 commands = pytest {posargs:tests}
 
 [testenv:flake8]