Adds new tests to verify enabling metrics for a single command.

Signed-off-by: Santiago Pericas-Geertsen <[email protected]>

fault-tolerance/fault-tolerance/pom.xml

@@ -154,6 +154,14 @@
                     </dependency>
                 </dependencies>
             </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <configuration>
+                    <forkCount>1</forkCount>
+                    <reuseForks>false</reuseForks>
+                </configuration>
+            </plugin>
         </plugins>
     </build>
 </project>

fault-tolerance/fault-tolerance/src/test/java/io/helidon/faulttolerance/MetricsEnableTest.java

@@ -0,0 +1,158 @@
+/*
+ * Copyright (c) 2025 Oracle and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.helidon.faulttolerance;
+
+import java.time.Duration;
+import java.util.NoSuchElementException;
+
+import io.helidon.config.Config;
+import io.helidon.metrics.api.Counter;
+import io.helidon.metrics.api.Tag;
+
+import org.hamcrest.Matchers;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import static io.helidon.faulttolerance.Bulkhead.FT_BULKHEAD_CALLS_TOTAL;
+import static io.helidon.faulttolerance.CircuitBreaker.FT_CIRCUITBREAKER_CALLS_TOTAL;
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.fail;
+
+class MetricsEnableTest extends CircuitBreakerBaseTest {
+
+    private static final long WAIT_TIMEOUT_MILLIS = 5000;
+
+    @BeforeAll
+    static void setupTest() {
+        FaultTolerance.config(Config.empty());      // empty config
+    }
+
+    @Test
+    void testEnableBulkhead() throws InterruptedException {
+        Bulkhead bulkhead = BulkheadConfig.builder()
+                .enableMetrics(true)    // metrics enabled
+                .build();
+
+        BulkheadBaseTest.Task inProgress = new BulkheadBaseTest.Task(0);
+        Async.invokeStatic(() -> bulkhead.invoke(inProgress::run));
+        if (!inProgress.waitUntilStarted(WAIT_TIMEOUT_MILLIS)) {
+            fail("Task inProgress not started");
+        }
+
+        Tag nameTag = Tag.create("name", bulkhead.name());
+        Counter callsTotal = MetricsUtils.counter(FT_BULKHEAD_CALLS_TOTAL, nameTag);
+        assertThat(callsTotal.count(), is(1L));
+    }
+
+    @Test
+    void testDisableBulkhead() throws InterruptedException {
+        Bulkhead bulkhead = BulkheadConfig.builder()
+                .enableMetrics(false)       // metrics disabled
+                .build();
+
+        BulkheadBaseTest.Task inProgress = new BulkheadBaseTest.Task(0);
+        Async.invokeStatic(() -> bulkhead.invoke(inProgress::run));
+        if (!inProgress.waitUntilStarted(WAIT_TIMEOUT_MILLIS)) {
+            fail("Task inProgress not started");
+        }
+
+        Tag nameTag = Tag.create("name", bulkhead.name());
+        assertThrows(NoSuchElementException.class,
+                     () -> MetricsUtils.counter(FT_BULKHEAD_CALLS_TOTAL, nameTag));
+    }
+
+    @Test
+    void testEnableCircuitBreaker() {
+        CircuitBreaker breaker = CircuitBreaker.builder()
+                .enableMetrics(true)        // metrics enabled
+                .delay(Duration.ofMillis(200))
+                .build();
+
+        good(breaker);
+        good(breaker);
+
+        Counter callsCounter = MetricsUtils.counter(FT_CIRCUITBREAKER_CALLS_TOTAL, Tag.create("name", breaker.name()));
+        assertThat(callsCounter.count(), Matchers.is(2L));
+    }
+
+    @Test
+    void testDisableCircuitBreaker() {
+        CircuitBreaker breaker = CircuitBreaker.builder()
+                .enableMetrics(false)        // metrics disabled
+                .delay(Duration.ofMillis(200))
+                .build();
+
+        good(breaker);
+        good(breaker);
+
+        assertThrows(NoSuchElementException.class,
+                     () -> MetricsUtils.counter(FT_CIRCUITBREAKER_CALLS_TOTAL, Tag.create("name", breaker.name())));
+    }
+
+    @Test
+    void testEnableRetry() {
+        Retry retry = Retry.builder()
+                .enableMetrics(true)        // metrics enabled
+                .build();
+
+        retry.invoke(() -> 0);
+
+        Tag nameTag = Tag.create("name", retry.name());
+        Counter callsCounter = MetricsUtils.counter(Retry.FT_RETRY_CALLS_TOTAL, nameTag);
+        assertThat(callsCounter.count(), is(1L));
+    }
+
+    @Test
+    void testDisableRetry() {
+        Retry retry = Retry.builder()
+                .enableMetrics(false)        // metrics disabled
+                .build();
+
+        retry.invoke(() -> 0);
+
+        Tag nameTag = Tag.create("name", retry.name());
+        assertThrows(NoSuchElementException.class,
+                     () -> MetricsUtils.counter(Retry.FT_RETRY_CALLS_TOTAL, nameTag));
+    }
+
+    @Test
+    void testEnableTimeout() {
+        Timeout timeout = Timeout.builder()
+                .enableMetrics(true)        // metrics enabled
+                .build();
+
+        timeout.invoke(() -> 0);
+
+        Tag nameTag = Tag.create("name", timeout.name());
+        Counter callsCounter = MetricsUtils.counter(Timeout.FT_TIMEOUT_CALLS_TOTAL, nameTag);
+        assertThat(callsCounter.count(), is(1L));
+    }
+
+    @Test
+    void testDisableTimeout() {
+        Timeout timeout = Timeout.builder()
+                .enableMetrics(false)        // metrics disabled
+                .build();
+
+        timeout.invoke(() -> 0);
+
+        Tag nameTag = Tag.create("name", timeout.name());
+        assertThrows(NoSuchElementException.class,
+                     () -> MetricsUtils.counter(Timeout.FT_TIMEOUT_CALLS_TOTAL, nameTag));
+    }
+}