git: calculate modified time of repository

This will be used for generating an HTML listing for v1 inboxes,
at least.  The logic for this follows that of grokmirror,
and we may dynamically generate manifest.js.gz natively...

1 files changed, 5 insertions, 0 deletions

diff --git a/t/git.t b/t/git.t
index d637e63b..5b612b8e 100644
--- a/t/git.t
+++ b/t/git.t
@@ -23,6 +23,7 @@ use_ok 'PublicInbox::Git';
 
 {
         my $gcf = PublicInbox::Git->new($dir);
+        is($gcf->modified, 749520000, 'modified time detected from commit');
         my $f = 'HEAD:foo.txt';
         my @x = $gcf->check($f);
         is(scalar @x, 3, 'returned 3 element array for existing file');
@@ -146,6 +147,10 @@ if ('alternates reloaded') {
         ok($gcf->cleanup(time - 30), 'cleanup did not expire');
         ok(!$gcf->cleanup(time + 30), 'cleanup can expire');
         ok(!$gcf->cleanup, 'cleanup idempotent');
+
+        my $t = $gcf->modified;
+        ok($t <= time, 'repo not modified in the future');
+        isnt($t, 0, 'repo not modified in 1970')
 }
 
 use_ok 'PublicInbox::Git', qw(git_unquote git_quote);