lib/PublicInbox/TestCommon.pm | 4 +++-

diff --git a/lib/PublicInbox/TestCommon.pm b/lib/PublicInbox/TestCommon.pm
index fb0d5a4e6ededaabcff6f78385b6e927fdac95bb..c3820d3a57463e44f19843541ec4003082a0874b 100644
--- a/lib/PublicInbox/TestCommon.pm
+++ b/lib/PublicInbox/TestCommon.pm
@@ -674,8 +674,10 @@ 	my $cb = pop;
 	my %opt = @_;
 	require PublicInbox::Lock;
 	require PublicInbox::InboxWritable;
+	require PublicInbox::Import;
 	my ($base) = ($0 =~ m!\b([^/]+)\.[^\.]+\z!);
-	my $dir = "t/data-gen/$base.$ident";
+	my ($db) = (PublicInbox::Import::default_branch() =~ m!([^/]+)\z!);
+	my $dir = "t/data-gen/$base.$ident-$db";
 	my $new = !-d $dir;
 	if ($new) {
 		mkdir $dir; # may race