tests/test-unrelated-pull

* clean up error handling when user requests to use a non file object
# HG changeset patch
# User [e-mail]
# Node ID 1ae21732349f5b6dba2941609a044d9c365a6fb2
# Parent  94744f6fe0e7c19b10fab7eb24249f3eeaa5489a
* clean up error handling when user requests to use a non file object
  - use os.path.exists() to verify the item exists
  - use os.path.isfile() to check whether the item is a file or not

diff -r 94744f6fe0e7 -r 1ae21732349f mercurial/hg.py

mkdir a
cd a
hg init
echo 123 > a
hg add a
hg commit -t "a" -u a -d "0 0"

cd ..
mkdir b
cd b
hg init 
echo 321 > b
hg add b
hg commit -t "b" -u b -d "0 0"

hg pull ../a
hg heads