support reloctable venv roots in testing framework

run_tests.sh, with_venv.sh, and the install_venv.py scripts now
support relocating the venv root to another location.

All 3 scripts now support new envinroment variables to configure
the location of the venv and the tools directory. To maintain
compatability the defaults are set to the current values.

venv_path = Location of the virtualenv directory
	Default: $(pwd)

venv_name = Name of the virtualenv directory
	Default: .venv

tools_path = Location of the tools directory
	Default: $(pwd)

Additionally the run_tests.sh script also takes these value as
arguments and will pass them along accordingly.

--virtual-env-path <path>   Location of the virtualenv directory
                             Default: $(pwd)
--virtual-env-name <name>   Name of the virtualenv directory
                             Default: .venv
--tools-path <dir>          Location of the tools directory
                             Default: $(pwd)

DocImpact

Change-Id: I1be036058227206ecca342f692cd3d6aadb24069
Fixes: bug #1116942

install_venv.py

@@ -28,7 +28,7 @@ os.sys.path.insert(0, parentdir)
 import install_venv_common as install_venv
 
 
-def print_help():
+def print_help(venv, root):
     help = """
     Nova development environment setup is complete.
 
@@ -38,21 +38,27 @@ def print_help():
     To activate the Nova virtualenv for the extent of your current shell
     session you can run:
 
-    $ source .venv/bin/activate
+    $ source %s/bin/activate
 
     Or, if you prefer, you can run commands in the virtualenv on a case by case
     basis by running:
 
-    $ tools/with_venv.sh <your command>
+    $ %s/tools/with_venv.sh <your command>
 
     Also, make test will automatically use the virtualenv.
     """
-    print help
+    print help % (venv, root)
 
 
 def main(argv):
     root = os.path.dirname(os.path.dirname(os.path.realpath(__file__)))
+
+    if os.environ.get('tools_path'):
+        root = os.environ['tools_path']
     venv = os.path.join(root, '.venv')
+    if os.environ.get('venv'):
+        venv = os.environ['venv']
+
     pip_requires = os.path.join(root, 'tools', 'pip-requires')
     test_requires = os.path.join(root, 'tools', 'test-requires')
     py_version = "python%s.%s" % (sys.version_info[0], sys.version_info[1])
@@ -65,7 +71,7 @@ def main(argv):
     install.create_virtualenv(no_site_packages=options.no_site_packages)
     install.install_dependencies()
     install.post_process()
-    print_help()
+    print_help(venv, root)
 
 if __name__ == '__main__':
     main(sys.argv)

with_venv.sh

@@ -1,4 +1,7 @@
 #!/bin/bash
-TOOLS=`dirname $0`
+tools_path=${tools_path:-$(dirname $0)}
-VENV=$TOOLS/../.venv
+venv_path=${venv_path:-${tools_path}}
-source $VENV/bin/activate && "$@"
+venv_dir=${venv_name:-/../.venv}
+TOOLS=${tools_path}
+VENV=${venv:-${venv_path}/${venv_dir}}
+source ${VENV}/bin/activate && "$@"