diff --git a/tools/tox_install.sh b/tools/tox_install.sh
new file mode 100755
index 000000000..43468e450
--- /dev/null
+++ b/tools/tox_install.sh
@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+
+# Client constraint file contains this client version pin that is in conflict
+# with installing the client from source. We should remove the version pin in
+# the constraints file before applying it for from-source installation.
+
+CONSTRAINTS_FILE=$1
+shift 1
+
+set -e
+
+# NOTE(tonyb): Place this in the tox enviroment's log dir so it will get
+# published to logs.openstack.org for easy debugging.
+localfile="$VIRTUAL_ENV/log/upper-constraints.txt"
+
+if [[ $CONSTRAINTS_FILE != http* ]]; then
+    CONSTRAINTS_FILE=file://$CONSTRAINTS_FILE
+fi
+# NOTE(tonyb): need to add curl to bindep.txt if the project supports bindep
+curl $CONSTRAINTS_FILE --insecure --progress-bar --output $localfile
+
+pip install -c$localfile openstack-requirements
+
+# This is the main purpose of the script: Allow local installation of
+# the current repo. It is listed in constraints file and thus any
+# install will be constrained and we need to unconstrain it.
+edit-constraints $localfile -- $CLIENT_NAME
+
+pip install -c$localfile -U $*
+exit $?
diff --git a/tox.ini b/tox.ini
index 573194eaf..8add2572d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,7 +1,7 @@
 # noted to use py34 you need virtualenv >= 1.11.4
 [tox]
 envlist = py35,py34,py27,pypy,pep8,docs
-minversion = 1.6
+minversion = 2.0
 skipsdist = True
 
 [testenv]
@@ -9,11 +9,14 @@ usedevelop = True
 # tox is silly... these need to be separated by a newline....
 whitelist_externals = find
                     bash
-install_command = pip install -U {opts} {packages}
+passenv = ZUUL_CACHE_DIR
+          REQUIREMENTS_PIP_LOCATION
+install_command = {toxinidir}/tools/tox_install.sh {env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt} {opts} {packages}
 setenv = VIRTUAL_ENV={envdir}
+         BRANCH_NAME=master
+         CLIENT_NAME=python-novaclient
 
-deps = -r{toxinidir}/requirements.txt
-       -r{toxinidir}/test-requirements.txt
+deps = -r{toxinidir}/test-requirements.txt
 commands =
   find . -type f -name "*.pyc" -delete
   bash tools/pretty_tox.sh '{posargs}'
@@ -41,6 +44,7 @@ commands = sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasen
 basepython = python2.7
 passenv = OS_NOVACLIENT_TEST_NETWORK
 setenv =
+  {[testenv]setenv}
   OS_TEST_PATH = ./novaclient/tests/functional
 commands = bash tools/pretty_tox.sh '--concurrency=1 {posargs}'
 
@@ -48,6 +52,7 @@ commands = bash tools/pretty_tox.sh '--concurrency=1 {posargs}'
 basepython = python3.4
 passenv = OS_NOVACLIENT_TEST_NETWORK
 setenv =
+  {[testenv]setenv}
   OS_TEST_PATH = ./novaclient/tests/functional
 commands = bash tools/pretty_tox.sh '--concurrency=1 {posargs}'