tests/test-clone-r

fix broken environment save/restore when a hook runs.
move "run commend with different env/cwd" code out to function in util.
new function is called esystem.

#!/bin/bash

hg init test
cd test
cat >>afile <<EOF
0
EOF
hg add afile
hg commit -m "0.0"
cat >>afile <<EOF
1
EOF
hg commit -m "0.1"
cat >>afile <<EOF
2
EOF
hg commit -m "0.2"
cat >>afile <<EOF
3
EOF
hg commit -m "0.3"
hg update -C 0
cat >>afile <<EOF
1
EOF
hg commit -m "1.1"
cat >>afile <<EOF
2
EOF
hg commit -m "1.2"
cat >fred <<EOF
a line
EOF
cat >>afile <<EOF
3
EOF
hg add fred
hg commit -m "1.3"
hg mv afile adifferentfile
hg commit -m "1.3m"
hg update -C 3
hg mv afile anotherfile
hg commit -m "0.3m"
hg debugindex .hg/data/afile.i
hg debugindex .hg/data/adifferentfile.i
hg debugindex .hg/data/anotherfile.i
hg debugindex .hg/data/fred.i
hg debugindex .hg/00manifest.i
hg verify
cd ..
for i in 0 1 2 3 4 5 6 7 8; do
   hg clone -r "$i" test test-"$i"
   cd test-"$i"
   hg verify
   cd ..
done
cd test-8
hg pull ../test-7
hg verify