diff --git a/e2e-docker/virtual_test.go b/e2e-docker/virtual_test.go
index f736ef8..02f7432 100644
--- a/e2e-docker/virtual_test.go
+++ b/e2e-docker/virtual_test.go
@@ -224,7 +224,7 @@ func TestVirtualDebSuite(t *testing.T) {
 		"echo \"deb [trusted=yes] $URL trixie-updates main\" > /etc/apt/sources.list.d/vdebs.list; " +
 		"apt-get update; " +
 		"idx=/tmp/avail; apt-cache dumpavail > $idx; " +
-		"grep -q '^Filename: vdebs-a/pool/' $idx; ! grep -q '^Filename: vdebs-b/' $idx; " +
+		"grep -q '^Filename: vdebs-a/pool/' $idx; if grep -q '^Filename: vdebs-b/' $idx; then echo 'vdebs-b not deduped'; exit 1; fi; " +
 		"pkg=$(awk '/^Package:/{p=$2} /^Size:/{if(!m||$2<m){m=$2;b=p}} END{print b}' $idx); " +
 		"cd /tmp && apt-get download $pkg && ls -l /tmp/*.deb"
 	out, err := exec.Command("docker", "run", "--rm", "--network", network,