diff --git a/.zuul.yaml b/.zuul.yaml
index 67a39c42..737eaf35 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -1,7 +1,11 @@
 - project:
     check:
       jobs:
-        - openstack-tox-lower-constraints
+        - openstack-tox-lower-constraints:
+            required-projects:
+              - openstack/horizon
     gate:
       jobs:
-        - openstack-tox-lower-constraints
+        - openstack-tox-lower-constraints:
+            required-projects:
+              - openstack/horizon
diff --git a/magnum_ui/karma.conf.js b/magnum_ui/karma.conf.js
index 80b88065..1a4543db 100644
--- a/magnum_ui/karma.conf.js
+++ b/magnum_ui/karma.conf.js
@@ -19,7 +19,7 @@ var path = require('path');
 
 module.exports = function (config) {
   // This tox venv is setup in the post-install npm step
-  var toxPath = '../.tox/karma/lib/python2.7/site-packages/';
+  var toxPath = '../.tox/karma/lib/python3.5/site-packages/';
 
   process.env.PHANTOMJS_BIN = 'node_modules/phantomjs-prebuilt/bin/phantomjs';
 
diff --git a/package.json b/package.json
index c67d54ac..9ad611b5 100644
--- a/package.json
+++ b/package.json
@@ -26,7 +26,7 @@
   },
   "dependencies": {},
   "scripts": {
-    "postinstall": "if [ ! -d .tox ] || [ ! -d .tox/karma ]; then tox -ekarma --notest; git clone https://git.openstack.org/openstack/horizon.git .tox/karma/src/horizon; pip install -U -t .tox/karma/lib/python2.7/site-packages/ .tox/karma/src/horizon; fi",
+    "postinstall": "if [ ! -d .tox ] || [ ! -d .tox/karma ]; then tox -ekarma --notest; pip install -U -t ./.tox/karma/lib/python3.5/site-packages/ ../horizon; fi",
     "lint": "eslint --no-color magnum_ui/static",
     "lintq": "eslint --quiet magnum_ui/static",
     "test": "karma start magnum_ui/karma.conf.js --single-run"
diff --git a/tools/tox_helper.sh b/tools/tox_helper.sh
deleted file mode 100755
index 8549089e..00000000
--- a/tools/tox_helper.sh
+++ /dev/null
@@ -1,20 +0,0 @@
-#!/usr/bin/env bash
-
-ENVNAME=$1
-BASEPYTHON=$2
-COMMAND=$3
-
-if [ ${COMMAND} = "pre" ]; then
-    # crean-up
-    rm -fr .tox/${ENVNAME}-log/
-    # install horizon from git
-    rm -fr .tox/${ENVNAME}/src/
-    git clone https://git.openstack.org/openstack/horizon.git .tox/${ENVNAME}/src/horizon
-    pip install -U -t .tox/${ENVNAME}/lib/${BASEPYTHON}/site-packages/ .tox/${ENVNAME}/src/horizon
-elif [ ${COMMAND} = "post" ]; then
-    # crean-up
-    rm -fr .tox/${ENVNAME}/src/
-    mv .tox/${ENVNAME}/log/ .tox/${ENVNAME}-log/
-    rm -fr .tox/${ENVNAME}/
-fi
-
diff --git a/tox.ini b/tox.ini
index 9a8ae06b..76142afe 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = pep8,py35,py35dj20,py27,eslint,karma,docs,releasenotes
+envlist = pep8,py27-local,py35-local,py35dj20-local,eslint,karma-local,docs-local,releasenotes,lower-constraints-local
 minversion = 2.3.2
 skipsdist = True
 
@@ -15,12 +15,20 @@ 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 manage.py test {posargs} --settings=magnum_ui.test.settings
+commands =
+  python manage.py test {posargs} --settings=magnum_ui.test.settings
+
+# For installation of horizon on local
+# NOTICE: this tox.ini requires horizon repository cloned in sibling directory.
+[testenv:hz-local]
+commands =
+  pip install -e ../horizon
 
 [testenv:venv]
 commands = {posargs}
 
 [testenv:pep8]
+basepython = python3.5
 commands = flake8 {posargs}
 
 [flake8]
@@ -34,68 +42,81 @@ commands =
   coverage xml --omit '.tox/cover/*' -o 'cover/coverage.xml'
   coverage html --omit '.tox/cover/*' -d 'cover/htmlcov'
 
+# NOTE(shu-mutow): On CI infra, horizon will be installed
+# according to job setting. but on local, we need to install
+# horizon from master branch.
 [testenv:py27]
-commands =
-  # Clean-up env and install horizon from git
-  {toxinidir}/tools/tox_helper.sh {envname} {basepython} pre
-  # Run test
-  python manage.py test {posargs}
-  # Clean-up env except log
-  {toxinidir}/tools/tox_helper.sh {envname} {basepython} post
+basepython = python2.7
 
-[testenv:py35]
+[testenv:py27-local]
+basepython = python2.7
+commands =
+  {[testenv:hz-local]commands}
+  {[testenv]commands}
+
+[testenv:py35-local]
 basepython = python3.5
 commands =
-  # Clean-up env and install horizon from git
-  {toxinidir}/tools/tox_helper.sh {envname} {basepython} pre
-  # Run test
-  python manage.py test {posargs}
-  # Clean-up env except log
-  {toxinidir}/tools/tox_helper.sh {envname} {basepython} post
+  {[testenv:hz-local]commands}
+  {[testenv]commands}
 
 [testenv:py35dj20]
 basepython = python3.5
 commands =
-  # Clean-up env and install horizon from git
-  {toxinidir}/tools/tox_helper.sh {envname} {basepython} pre
-  # Run test
-  pip install django>=2.0,<2.1
-  python manage.py test {posargs}
-  # Clean-up env except log
-  {toxinidir}/tools/tox_helper.sh {envname} {basepython} post
+  {[testenv:hz-local]commands}
+  {[testenv]commands}
+
+[testenv:py35dj20-local]
+basepython = python3.5
+commands =
+  {[testenv:hz-local]commands}
+  pip install -U django>=2.0,<2.1
+  {[testenv]commands}
 
 [testenv:eslint]
+basepython = python3.5
 whitelist_externals =
   npm
 commands =
-  # Clean-up env and install horizon from git
-  {toxinidir}/tools/tox_helper.sh {envname} {basepython} pre
-  # Run test
   npm install
   npm run lint
-  # Clean-up env except log
-  {toxinidir}/tools/tox_helper.sh {envname} {basepython} post
 
+# NOTE(shu-mutow): The "postinstall" script on package.json will install horizon
+# from master branch into karma environment with py35 for testing javascripts.
+# Horizon from master is needed to be cloned into ../horizon on both local and CI.
 [testenv:karma]
+basepython = python3.5
 whitelist_externals =
-  npm
+  {[testenv:eslint]whitelist_externals}
 commands =
-  # Clean-up env and install horizon from git
-  {toxinidir}/tools/tox_helper.sh {envname} {basepython} pre
-  # Run test
   npm install
   npm run test
-  # Clean-up env except log
-  {toxinidir}/tools/tox_helper.sh {envname} {basepython} post
+
+[testenv:karma-local]
+basepython = python3.5
+whitelist_externals =
+  {[testenv:eslint]whitelist_externals}
+commands =
+  {[testenv:karma]commands}
 
 [testenv:docs]
+basepython = python3.5
 deps =
   -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
   -r{toxinidir}/doc/requirements.txt
 commands=
   sphinx-build -W -b html doc/source doc/build/html
 
+[testenv:docs-local]
+basepython = python3.5
+deps =
+  {[testenv:docs]deps}
+commands=
+  {[testenv:hz-local]commands}
+  {[testenv:docs]commands}
+
 [testenv:releasenotes]
+basepython = python3.5
 deps =
   {[testenv:docs]deps}
 commands =
@@ -107,3 +128,12 @@ deps =
   -c{toxinidir}/lower-constraints.txt
   -r{toxinidir}/test-requirements.txt
   -r{toxinidir}/requirements.txt
+
+[testenv:lower-constraints-local]
+basepython = python3
+deps =
+  {[testenv:lower-constraints]deps}
+commands =
+  {[testenv:hz-local]commands}
+  {[testenv]commands}
+