Remove install of horizon from test-requirements

The entry to install horizon in the test requirements is problematic
when installing in devstack.  Users have reported issues with
multiple requirements for horizon or a problem with not being able
to access git on some machines to pull down the horizon code.

However, the tox tests still require the horizon code so that the
unit tests can run against the horizon code.

The solution is to remove the horizon entry in the
test-requirements.txt.

Also added the pip-install.sh script (which is "borrowed" from
Sahara to which we express our most heartfelt thanks) to perform the
pip install along with the pull of the horizon code from git.

Finally, invoked the pip-install.sh script in the tox.ini file.

Change-Id: Idb5edf32a461ada99aa1f189635ef34e9cbe1a58
Closes-Bug: #1562081

test-requirements.txt

@@ -2,8 +2,6 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 
--e git://github.com/openstack/horizon.git#egg=horizon
-
 hacking<0.11,>=0.10.0
 coverage>=3.6
 ddt>=0.7.0

tools/pip_install.sh

@@ -0,0 +1,56 @@
+#!/bin/sh
+
+# This script is borrowed from Sahara who borrowed from neutron-* repos.
+
+# Many of horizon's repos suffer from the problem of depending on horizon,
+# but it not existing on pypi.
+
+# This wrapper for tox's package installer will use the existing package
+# if it exists, else use zuul-cloner if that program exists, else grab it
+# from horizon master via a hard-coded URL. That last case should only
+# happen with devs running unit tests locally.
+
+# From the tox.ini config page:
+# install_command=ARGV
+# default:
+# pip install {opts} {packages}
+
+ZUUL_CLONER=/usr/zuul-env/bin/zuul-cloner
+BRANCH_NAME=master
+horizon_installed=$(echo "import horizon" | python 2>/dev/null ; echo $?)
+
+set -e
+
+install_cmd="pip install"
+if [ "$1" = "constrained" ]; then
+    install_cmd="$install_cmd $2"
+    shift
+fi
+shift
+
+if [ $horizon_installed -eq 0 ]; then
+    echo "ALREADY INSTALLED" > /tmp/tox_install.txt
+    echo "Horizon already installed; using existing package"
+elif [ -x "$ZUUL_CLONER" ]; then
+    export ZUUL_BRANCH=${ZUUL_BRANCH-$BRANCH}
+    echo "ZUUL CLONER" > /tmp/tox_install.txt
+    cwd=$(/bin/pwd)
+    cd /tmp
+    $ZUUL_CLONER --cache-dir \
+        /opt/git \
+        --branch $BRANCH_NAME \
+        git://git.openstack.org \
+        openstack/horizon
+    cd openstack/horizon
+    $install_cmd -e .
+    cd "$cwd"
+else
+    echo "PIP HARDCODE" > /tmp/tox_install.txt
+    if [ -z "$HORIZON_PIP_LOCATION" ]; then
+        HORIZON_PIP_LOCATION="git+https://git.openstack.org/openstack/horizon@$BRANCH_NAME#egg=horizon"
+    fi
+    $install_cmd -U -e ${HORIZON_PIP_LOCATION}
+fi
+
+$install_cmd -U $*
+exit $?

tox.ini

@@ -5,7 +5,7 @@ skipsdist = True
 
 [testenv]
 usedevelop = True
-install_command = pip install -U {opts} {packages}
+install_command = {toxinidir}/tools/pip_install.sh unconstrained {opts} {packages}
 setenv =
    VIRTUAL_ENV={envdir}
 deps = -r{toxinidir}/requirements.txt