pass user and home through from tox instead of using id to derive them

The id command being used does not work on Linux.

Author: dhellmann

tests/setup.sh

@@ -10,8 +10,3 @@ export WORKON_HOME=$(mktemp -d -t "WORKON_HOME.XXXX.$$")
 export PROJECT_HOME=$(mktemp -d -t "PROJECT_HOME.XXXX.$$")
 
 #unset HOOK_VERBOSE_OPTION
-
-# tox no longer exports these variables by default, so set them
-# ourselves to ensure the tests that rely on the values work
-export USER=$(id -u -n)
-export HOME=$(id -P | cut -f9 -d:)

tox.ini

@@ -5,6 +5,9 @@ envlist = py,zsh,style
 install_command = pip install -U {opts} {packages}
 commands = bash ./tests/run_tests {envdir} []
 deps = -rrequirements.txt
+pass_env =
+    HOME
+    USER
 setenv =
     TOXIC = true
     SHELL = /bin/bash