diff --git a/tools/tox_install.sh b/tools/tox_install.sh
new file mode 100755
index 0000000..e61b63a
--- /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 d3501f1..db7f7bb 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,8 +1,13 @@
 [tox]
-minversion = 1.6
+minversion = 2.0
 envlist = py34,py27,pep8
 
 [testenv]
+setenv =
+    VIRTUAL_ENV={envdir}
+    BRANCH_NAME=master
+    CLIENT_NAME=pycadf
+install_command = {toxinidir}/tools/tox_install.sh {env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt} {opts} {packages}
 deps = -r{toxinidir}/test-requirements.txt
 commands = python setup.py testr --slowest --testr-args='{posargs}'