worker: add basic test to ensure child processes are managed well

This should catch the bug fixed by "worker: ignore meaningless exit status
indication returned by os.waitpid()."

Before, worker.py was untested since test repositories are relatively small.

tests/test-simple-update.t

@@ -1,58 +1,92 b''
   $ hg init test
   $ cd test
   $ echo foo>foo
   $ hg addremove
   adding foo
   $ hg commit -m "1"
 
   $ hg verify
   checking changesets
   checking manifests
   crosschecking files in changesets and manifests
   checking files
   1 files, 1 changesets, 1 total revisions
 
   $ hg clone . ../branch
   updating to branch default
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ cd ../branch
   $ hg co
   0 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ echo bar>>foo
   $ hg commit -m "2"
 
   $ cd ../test
 
   $ hg pull ../branch
   pulling from ../branch
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files
   (run 'hg update' to get a working copy)
 
   $ hg verify
   checking changesets
   checking manifests
   crosschecking files in changesets and manifests
   checking files
   1 files, 2 changesets, 2 total revisions
 
   $ hg co
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
 
   $ cat foo
   foo
   bar
 
   $ hg manifest --debug
   6f4310b00b9a147241b071a60c28a650827fb03d 644   foo
 
 update to rev 0 with a date
 
   $ hg upd -d foo 0
   abort: you can't specify a revision and a date
   [255]
 
   $ cd ..
+
+update with worker processes
+
+#if no-windows
+
+  $ cat <<EOF > forceworker.py
+  > from mercurial import extensions, worker
+  > def nocost(orig, ui, costperop, nops):
+  >     return worker._numworkers(ui) > 1
+  > def uisetup(ui):
+  >     extensions.wrapfunction(worker, 'worthwhile', nocost)
+  > EOF
+
+  $ hg init worker
+  $ cd worker
+  $ cat <<EOF >> .hg/hgrc
+  > [extensions]
+  > forceworker = $TESTTMP/forceworker.py
+  > [worker]
+  > numcpus = 4
+  > EOF
+  $ for i in `python $TESTDIR/seq.py 1 100`; do
+  >   echo $i > $i
+  > done
+  $ hg ci -qAm 'add 100 files'
+
+  $ hg update null
+  0 files updated, 0 files merged, 100 files removed, 0 files unresolved
+  $ hg update
+  100 files updated, 0 files merged, 0 files removed, 0 files unresolved
+
+  $ cd ..
+
+#endif