diff --git a/docs/testing.md b/docs/testing.md
index e7ac883..cfa94d9 100644
--- a/docs/testing.md
+++ b/docs/testing.md
@@ -114,13 +114,19 @@ had.
 export KVM_TEST_HOST=nas1.home.lan:22          # SSH endpoint
 export KVM_TEST_USER=virt                      # must be in the libvirt group
 export KVM_TEST_SSH_KEY=$HOME/.ssh/id_ed25519  # private key for that user
+export KVM_TEST_KNOWN_HOSTS=$HOME/.ssh/kvm_known_hosts  # the hypervisors' host keys
 export KVM_TEST_BRIDGE=br0                     # bridge to a network with DHCP
 export KVM_TEST_IMAGE_URL=https://cloud.debian.org/images/cloud/trixie/latest/debian-13-generic-amd64.qcow2
 make test-integration-kvm
 ```
 
-Optional: `KVM_TEST_KNOWN_HOSTS` (without it host keys are **not**
-verified — the log says so), `KVM_TEST_IMAGE_SHA256`, `KVM_TEST_POOL`
+`KVM_TEST_KNOWN_HOSTS` is technically optional, but leaving it out turns
+host-key verification **off** for the run (the log says so); keep a
+`kvm_known_hosts` holding just the hypervisors rather than pointing the
+test at your everyday `known_hosts`, so a re-keyed hypervisor is a
+one-line fix in a file nothing else uses.
+
+Also optional: `KVM_TEST_IMAGE_SHA256`, `KVM_TEST_POOL`
 (default `default`), `KVM_TEST_SOCKET`, `KVM_TEST_TIMEOUT` (default
 `20m`, must cover the first-time image download), `KVM_TEST_KEEP`
 to leave the VM behind for `virsh console` when something goes wrong,