devel: add a config field to force dates to timestamp 0
Add a new config field named default-date under the devel section to force all
implicits date to a specific value. If a explicit date is passed, it will
override the default.
This patch only affect changesets. Other usages (blackbox, obsmarkers) are
updated in later patchs.
The test runner is setting a bunch of alias to force the '--date' argument. We
will replace theses aliases in a later patch.
running: init test1
result: None
running: add foo
result: 0
running: commit -m commit1 -d 2000-01-01 foo
result: None
running: commit -m commit2 -d 2000-01-02 foo
result: None
running: log -r 0
changeset: 0:0e4634943879
user: test
date: Sat Jan 01 00:00:00 2000 +0000
summary: commit1
result: None
running: log -r tip
changeset: 1:45589e459b2e
tag: tip
user: test
date: Sun Jan 02 00:00:00 2000 +0000
summary: commit2
result: None