mda: set GIT_AUTHOR_DATE in commits as well

While we're at it, write some quick tests.

1 files changed, 1 insertions, 0 deletions

diff --git a/public-inbox-mda b/public-inbox-mda
index 14017f68..411ac15f 100755
--- a/public-inbox-mda
+++ b/public-inbox-mda
@@ -52,6 +52,7 @@ if (PublicInbox->precheck($filter, $recipient) &&
                         defined $email or $email = "";
                         local $ENV{GIT_AUTHOR_NAME} = $name;
                         local $ENV{GIT_AUTHOR_EMAIL} = $email;
+                        local $ENV{GIT_AUTHOR_DATE} = $simple->header("Date");
                         local $ENV{GIT_COMMITTER_EMAIL} = $recipient;
                         local $ENV{GIT_COMMITTER_NAME} = $dst->{listname};