diff --git a/core/src/test/java/com/linecorp/armeria/server/ServerTlsCertificateMetricsTest.java b/core/src/test/java/com/linecorp/armeria/server/ServerTlsCertificateMetricsTest.java
index d78ab0e4002..7a2371976af 100644
--- a/core/src/test/java/com/linecorp/armeria/server/ServerTlsCertificateMetricsTest.java
+++ b/core/src/test/java/com/linecorp/armeria/server/ServerTlsCertificateMetricsTest.java
@@ -181,7 +181,7 @@ void tlsMetricGivenCertificateChainExpired() {
               .build();
 
         assertThatGauge(meterRegistry, CERT_VALIDITY_GAUGE_NAME, "localhost").isZero();
-        assertThatGauge(meterRegistry, CERT_VALIDITY_DAYS_GAUGE_NAME, "localhost").isEqualTo(-1);
+        assertThatGauge(meterRegistry, CERT_VALIDITY_DAYS_GAUGE_NAME, "localhost").isLessThanOrEqualTo(-1);
         assertThatGauge(meterRegistry, CERT_VALIDITY_GAUGE_NAME, "test.root.armeria").isOne();
         assertThatGauge(meterRegistry, CERT_VALIDITY_DAYS_GAUGE_NAME, "test.root.armeria").isPositive();
     }