cmd/promtool: fix panic with empty exp_labels
@@ -286,6 +286,9 @@ func (tg *testGroup) test(mint, maxt time.Time, evalInterval time.Duration, grou
for _, a := range testcase.ExpAlerts {
// User gives only the labels from alerting rule, which doesn't
// include this label (added by Prometheus during Eval).
+ if a.ExpLabels == nil {
+ a.ExpLabels = make(map[string]string)
+ }
a.ExpLabels[labels.AlertName] = testcase.Alertname
expAlerts = append(expAlerts, labelAndAnnotation{
