inboxwritable: add assert_usable_dir sub

And use it for mda, since "0" could be a usable directory
if somebody insists on using relative paths...

1 files changed, 8 insertions, 0 deletions

diff --git a/t/import.t b/t/import.t
index 4ec3c4f3..d309eec5 100644
--- a/t/import.t
+++ b/t/import.t
@@ -96,4 +96,12 @@ is(undef, $im->checkpoint, 'checkpoint works before ->done');
 $im->done;
 is(undef, $im->checkpoint, 'checkpoint works after ->done');
 $im->checkpoint;
+
+my $nogit = PublicInbox::Git->new("$dir/non-existent/dir");
+eval {
+        my $nope = PublicInbox::Import->new($nogit, 'nope', 'no@example.com');
+        $nope->add($mime);
+};
+ok($@, 'Import->add fails on non-existent dir');
+
 done_testing();