run-tests.py: avoid using popen2.Popen4 - use subprocess instead
Use subprocess to emulate Popen4 if available - similar to how it is done in
util.py.
Using popen2 under python 2.6 gives
DeprecationWarning: The popen2 module is deprecated. Use the subprocess module.
#!/bin/sh
hg init
echo a > a
hg commit -A -ma
echo a >> a
hg commit -mb
echo a >> a
hg commit -mc
hg up 1
echo a >> a
hg commit -md
hg up 1
echo a >> a
hg commit -me
hg up 1
echo % should fail because not at a head
hg merge
hg up
echo % should fail because \> 2 heads
hg merge
echo % should succeed
hg merge 2
hg commit -mm1
echo % should succeed - 2 heads
hg merge
hg commit -mm2
echo % should fail because at tip
hg merge
hg up 0
echo % should fail because 1 head
hg merge
true