diff --git a/jeannie b/jeannie
index 2dfff26..4552558 100755
--- a/jeannie
+++ b/jeannie
@@ -4344,7 +4344,7 @@ cluster_worker_targets() {
     if [[ -s "${var_file}" ]] && command -v python3 >/dev/null 2>&1; then
         while IFS= read -r target; do
             [[ -n "${target}" ]] || continue
-            if [[ ! " ${CLUSTER_WORKER_TARGETS[*]} " =~ [[:space:]]${target}[[:space:]] ]]; then
+            if [[ ! " ${CLUSTER_WORKER_TARGETS[*]-} " =~ [[:space:]]${target}[[:space:]] ]]; then
                 CLUSTER_WORKER_TARGETS+=("${target}")
             fi
         done < <(python3 - "${var_file}" <<'PY'
@@ -6585,6 +6585,11 @@ Destructive
 EOF
 }
 
+if [[ "${JEANNIE_LIBRARY_MODE:-false}" == "true" ]]; then
+    # shellcheck disable=SC2317
+    return 0 2>/dev/null || exit 0
+fi
+
 case "${1:-}" in
     "" | help | -h | --help)
         print_usage
diff --git a/scripts/validate-homelab b/scripts/validate-homelab
index 707d43c..8457f7a 100755
--- a/scripts/validate-homelab
+++ b/scripts/validate-homelab
@@ -87,9 +87,14 @@ validate_security_static() {
     fi
 }
 
+validate_unit_tests() {
+    "${REPO_ROOT}/tests/jeannie-unit"
+}
+
 main() {
     cd "${REPO_ROOT}"
     run_step "Inventory" "${REPO_ROOT}/scripts/validate-homelab-inventory" "${HOMELAB_INVENTORY_FILE:-${REPO_ROOT}/homelab.yml}"
+    run_step "Unit tests" validate_unit_tests
     run_step "Generated docs" "${REPO_ROOT}/scripts/render-docs" --check
     run_step "Bash syntax" validate_bash_syntax
     run_step "Shellcheck" validate_shellcheck
diff --git a/tests/jeannie-unit b/tests/jeannie-unit
new file mode 100755
index 0000000..116484e
--- /dev/null
+++ b/tests/jeannie-unit
@@ -0,0 +1,147 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+LAB_DIR="${REPO_ROOT}/.lab"
+TMP_DIR="$(mktemp -d "${TMPDIR:-/tmp}/jeannie-unit.XXXXXX")"
+BACKUP_DIR="${TMP_DIR}/backup"
+FAILURES=0
+
+mkdir -p "${BACKUP_DIR}" "${LAB_DIR}" "${TMP_DIR}/bin"
+
+cleanup() {
+    for file in pimox-workers.tsv cluster-workers.auto.tfvars.json; do
+        rm -f "${LAB_DIR}/${file}"
+        if [[ -f "${BACKUP_DIR}/${file}" ]]; then
+            cp "${BACKUP_DIR}/${file}" "${LAB_DIR}/${file}"
+        fi
+    done
+    rm -rf "${TMP_DIR}"
+}
+trap cleanup EXIT
+
+for file in pimox-workers.tsv cluster-workers.auto.tfvars.json; do
+    if [[ -f "${LAB_DIR}/${file}" ]]; then
+        cp "${LAB_DIR}/${file}" "${BACKUP_DIR}/${file}"
+    fi
+done
+
+cat >"${TMP_DIR}/bin/tofu" <<'EOF'
+#!/usr/bin/env bash
+exit 1
+EOF
+chmod +x "${TMP_DIR}/bin/tofu"
+export PATH="${TMP_DIR}/bin:${PATH}"
+
+cat >"${LAB_DIR}/pimox-workers.tsv" <<'EOF'
+pimox01	192.168.100.66	jv	pimox-worker-01	/home/jv/.ssh/id_ed25519
+pimox02	192.168.100.67	jv	pimox-worker-02	/home/jv/.ssh/id_ed25519
+pimox03	192.168.100.76	jv	pimox-worker-03	/home/jv/.ssh/id_ed25519
+EOF
+
+cat >"${LAB_DIR}/cluster-workers.auto.tfvars.json" <<'EOF'
+{
+  "worker_nodes": {
+    "pimox01": {
+      "host": "192.168.100.66",
+      "user": "jv",
+      "node_name": "pimox-worker-01",
+      "ssh_private_key_path": "/home/jv/.ssh/id_ed25519"
+    },
+    "pimox02": {
+      "host": "192.168.100.67",
+      "user": "jv",
+      "node_name": "pimox-worker-02",
+      "ssh_private_key_path": "/home/jv/.ssh/id_ed25519"
+    },
+    "pimox03": {
+      "host": "192.168.100.76",
+      "user": "jv",
+      "node_name": "pimox-worker-03",
+      "ssh_private_key_path": "/home/jv/.ssh/id_ed25519"
+    },
+    "manual01": {
+      "host": "192.168.100.99",
+      "user": "jv",
+      "node_name": "manual-worker-01",
+      "ssh_private_key_path": "/home/jv/.ssh/id_ed25519"
+    }
+  }
+}
+EOF
+
+export JEANNIE_LIBRARY_MODE=true
+# shellcheck disable=SC1091
+source "${REPO_ROOT}/jeannie"
+
+pass() {
+    printf 'ok    %s\n' "$1"
+}
+
+fail() {
+    printf 'fail  %s\n' "$1"
+    FAILURES=$((FAILURES + 1))
+}
+
+assert_eq() {
+    local label="$1"
+    local expected="$2"
+    local actual="$3"
+
+    if [[ "${actual}" == "${expected}" ]]; then
+        pass "${label}"
+    else
+        fail "${label}: expected '${expected}', got '${actual}'"
+    fi
+}
+
+test_pimox_worker_count_detects_generated_topology() {
+    unset LAB_PIMOX_WORKER_COUNT
+    assert_eq "detects 3 generated Pimox workers" "3" "$(pimox_worker_count_default)"
+}
+
+test_configured_worker_count_cannot_hide_existing_workers() {
+    LAB_PIMOX_WORKER_COUNT=1
+    assert_eq "effective count keeps detected 3 workers" "3" "$(pimox_worker_count_effective)"
+    unset LAB_PIMOX_WORKER_COUNT
+}
+
+test_configured_worker_count_can_expand_target_set() {
+    LAB_PIMOX_WORKER_COUNT=4
+    assert_eq "effective count allows explicit expansion" "4" "$(pimox_worker_count_effective)"
+    unset LAB_PIMOX_WORKER_COUNT
+}
+
+test_cluster_worker_targets_include_pimox_and_manual_workers() {
+    CLUSTER_WORKER_TARGETS=()
+    cluster_worker_targets
+    local targets
+    targets="$(printf '%s\n' "${CLUSTER_WORKER_TARGETS[@]}" | sort | paste -sd ',' -)"
+    assert_eq "cluster targets include generated Pimox workers" "jv@192.168.100.66,jv@192.168.100.67,jv@192.168.100.76,jv@192.168.100.99" "${targets}"
+}
+
+test_report_renderer_hides_ok_links() {
+    local output
+    output="$(
+        printf 'ok\tArea\tHealthy\tok\tdetail\tfix\tgraph\tquery\nwarn\tArea\tWarning\tneeds attention\tdetail\tfix\tgraph\tquery\n' |
+            "${REPO_ROOT}/scripts/report-render" --title "Unit Report" --only all
+    )"
+    if grep -A4 'Healthy' <<<"${output}" | grep -Eq 'graph:|query:'; then
+        fail "report renderer hides graph/query for ok rows"
+    else
+        pass "report renderer hides graph/query for ok rows"
+    fi
+}
+
+test_pimox_worker_count_detects_generated_topology
+test_configured_worker_count_cannot_hide_existing_workers
+test_configured_worker_count_can_expand_target_set
+test_cluster_worker_targets_include_pimox_and_manual_workers
+test_report_renderer_hides_ok_links
+
+if ((FAILURES > 0)); then
+    printf '\n%s unit test(s) failed.\n' "${FAILURES}" >&2
+    exit 1
+fi
+
+printf '\nAll jeannie unit tests passed.\n'