Fix use of venv in Tempest.

Currently when running Tempest tests with run_tests.sh a venv
isn't being used. This leaves tempest at the mercy of whatever
required package versions are installed on the system.

This patch takes install_venv.py and with_venv.sh from nova and
integrates them into run_tests to ensure that the correct
dependencies versions from pip-requires and test-requires are
being used.

Change-Id: I4bf4a02890a33c4034e4493d1763ed4019fdf46e
diff --git a/run_tests.sh b/run_tests.sh
index 7016a30..af33f7c 100755
--- a/run_tests.sh
+++ b/run_tests.sh
@@ -4,6 +4,10 @@
   echo "Usage: $0 [OPTION]..."
   echo "Run Tempest test suite"
   echo ""
+  echo "  -V, --virtual-env        Always use virtualenv.  Install automatically if not present"
+  echo "  -N, --no-virtual-env     Don't use virtualenv.  Run tests in local environment"
+  echo "  -s, --no-site-packages   Isolate the virtualenv from the global Python environment"
+  echo "  -f, --force              Force a clean re-build of the virtual environment. Useful when dependencies have been added."
   echo "  -s, --smoke              Only run smoke tests"
   echo "  -w, --whitebox           Only run whitebox tests"
   echo "  -p, --pep8               Just run pep8"
@@ -15,6 +19,10 @@
 function process_option {
   case "$1" in
     -h|--help) usage;;
+    -V|--virtual-env) always_venv=1; never_venv=0;;
+    -N|--no-virtual-env) always_venv=0; never_venv=1;;
+    -s|--no-site-packages) no_site_packages=1;;
+    -f|--force) force=1;;
     -d|--debug) set -o xtrace;;
     -p|--pep8) let just_pep8=1;;
     -s|--smoke) noseargs="$noseargs --attr=type=smoke";;
@@ -25,6 +33,14 @@
 
 noseargs=""
 just_pep8=0
+venv=.venv
+with_venv=tools/with_venv.sh
+always_venv=0
+never_venv=0
+no_site_packages=0
+force=0
+wrapper=""
+
 
 export NOSE_WITH_OPENSTACK=1
 export NOSE_OPENSTACK_COLOR=1
@@ -37,6 +53,9 @@
   process_option $arg
 done
 
+if [ $no_site_packages -eq 1 ]; then
+  installvenvopts="--no-site-packages"
+fi
 
 # only add tempest default if we don't specify a test
 if [[ "x$noseargs" =~ "tempest" ]]; then
@@ -47,7 +66,7 @@
 
 
 function run_tests {
-  $NOSETESTS
+  ${wrapper} $NOSETESTS
 }
 
 function run_pep8 {
@@ -58,7 +77,7 @@
 
   ignore='--ignore=N4,E121,E122,E125,E126'
   
-  python tools/hacking.py ${ignore} ${srcfiles}
+  ${wrapper} python tools/hacking.py ${ignore} ${srcfiles}
 }
 
 NOSETESTS="nosetests $noseargs"
@@ -68,6 +87,32 @@
     exit
 fi
 
+if [ $never_venv -eq 0 ]
+then
+  # Remove the virtual environment if --force used
+  if [ $force -eq 1 ]; then
+    echo "Cleaning virtualenv..."
+    rm -rf ${venv}
+  fi
+  if [ -e ${venv} ]; then
+    wrapper="${with_venv}"
+  else
+    if [ $always_venv -eq 1 ]; then
+      # Automatically install the virtualenv
+      python tools/install_venv.py $installvenvopts
+      wrapper="${with_venv}"
+    else
+      echo -e "No virtual environment found...create one? (Y/n) \c"
+      read use_ve
+      if [ "x$use_ve" = "xY" -o "x$use_ve" = "x" -o "x$use_ve" = "xy" ]; then
+        # Install the virtualenv and run the test suite in it
+        python tools/install_venv.py $installvenvopts
+        wrapper=${with_venv}
+      fi
+    fi
+  fi
+fi
+
 run_tests || exit
 
 if [ -z "$noseargs" ]; then