diff --git a/tools/tox_install.sh b/tools/tox_install.sh
deleted file mode 100755
index 5cc33e8..0000000
--- a/tools/tox_install.sh
+++ /dev/null
@@ -1,53 +0,0 @@
-#!/usr/bin/env bash
-
-# [liujiong] This file is refer to tox_install.sh in neutron-lib.
-# Library constraint file contains this library version pin that is in conflict
-# with installing the library from source. We should replace the version pin in
-# the constraints file before applying it for from-source installation.
-
-ZUUL_CLONER=/usr/zuul-env/bin/zuul-cloner
-BRANCH_NAME=master
-LIB_NAME=castellan
-requirements_installed=$(echo "import openstack_requirements" | python 2>/dev/null ; echo $?)
-
-set -e
-
-CONSTRAINTS_FILE=$1
-shift
-
-install_cmd="pip install"
-mydir=$(mktemp -dt "$LIB_NAME-tox_install-XXXXXXX")
-trap "rm -rf $mydir" EXIT
-localfile=$mydir/upper-constraints.txt
-if [[ $CONSTRAINTS_FILE != http* ]]; then
-    CONSTRAINTS_FILE=file://$CONSTRAINTS_FILE
-fi
-curl $CONSTRAINTS_FILE -k -o $localfile
-install_cmd="$install_cmd -c$localfile"
-
-if [ $requirements_installed -eq 0 ]; then
-    echo "Requirements already installed; using existing package"
-elif [ -x "$ZUUL_CLONER" ]; then
-    pushd $mydir
-    $ZUUL_CLONER --cache-dir \
-        /opt/git \
-        --branch $BRANCH_NAME \
-        git://git.openstack.org \
-        openstack/requirements
-    cd openstack/requirements
-    $install_cmd -e .
-    popd
-else
-    if [ -z "$REQUIREMENTS_PIP_LOCATION" ]; then
-        REQUIREMENTS_PIP_LOCATION="git+https://git.openstack.org/openstack/requirements@$BRANCH_NAME#egg=requirements"
-    fi
-    $install_cmd -U -e ${REQUIREMENTS_PIP_LOCATION}
-fi
-
-# 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 -- $LIB_NAME "-e file://$PWD#egg=$LIB_NAME"
-
-$install_cmd -U $*
-exit $?
diff --git a/tox.ini b/tox.ini
index 7f8c473..3debb18 100644
--- a/tox.ini
+++ b/tox.ini
@@ -5,11 +5,13 @@
 
 [testenv]
 usedevelop = True
-install_command = {toxinidir}/tools/tox_install.sh {env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt} {opts} {packages}
+install_command = pip install {opts} {packages}
 setenv =
    VIRTUAL_ENV={envdir}
    OS_TEST_PATH=./castellan/tests/unit
-deps = -r{toxinidir}/requirements.txt
+deps =
+       -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
+       -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 commands = python setup.py testr --slowest --testr-args='{posargs}'
 
@@ -53,8 +55,6 @@
 setenv =
     VIRTUAL_ENV={envdir}
     OS_TEST_PATH=./castellan/tests/functional
-deps = -r{toxinidir}/requirements.txt
-       -r{toxinidir}/test-requirements.txt
 commands = python setup.py testr --slowest --testr-args='{posargs}'
 
 [testenv:functional-vault]
@@ -64,8 +64,6 @@
 setenv =
     VIRTUAL_ENV={envdir}
     OS_TEST_PATH=./castellan/tests/functional
-deps = -r{toxinidir}/requirements.txt
-       -r{toxinidir}/test-requirements.txt
 commands =
     {toxinidir}/tools/setup-vault-env.sh pifpaf -e VAULT_TEST run vault -- python setup.py testr --slowest --testr-args='{posargs}'