(fluss) branch main updated: [test] Fix flaky CoordinatorEventManagerTest by isolating metric group instance (#3252)

[yunhong]

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swuferhong pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/fluss.git


The following commit(s) were added to refs/heads/main by this push:
     new c7878e8d1 [test] Fix flaky CoordinatorEventManagerTest by isolating 
metric group instance (#3252)
c7878e8d1 is described below

commit c7878e8d1de1ced05855ddb2dd8a1f1d238f38a1
Author: yunhong <337361...@qq.com>
AuthorDate: Wed May 6 11:20:15 2026 +0800

    [test] Fix flaky CoordinatorEventManagerTest by isolating metric group 
instance (#3252)
---
 .../event/CoordinatorEventManagerTest.java          | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git 
a/fluss-server/src/test/java/org/apache/fluss/server/coordinator/event/CoordinatorEventManagerTest.java
 
b/fluss-server/src/test/java/org/apache/fluss/server/coordinator/event/CoordinatorEventManagerTest.java
index 48bfd51bc..36fb8bf15 100644
--- 
a/fluss-server/src/test/java/org/apache/fluss/server/coordinator/event/CoordinatorEventManagerTest.java
+++ 
b/fluss-server/src/test/java/org/apache/fluss/server/coordinator/event/CoordinatorEventManagerTest.java
@@ -21,9 +21,10 @@ import org.apache.fluss.cluster.Endpoint;
 import org.apache.fluss.cluster.ServerType;
 import org.apache.fluss.metrics.Gauge;
 import org.apache.fluss.metrics.MetricNames;
+import org.apache.fluss.metrics.registry.NOPMetricRegistry;
 import org.apache.fluss.server.coordinator.CoordinatorContext;
 import org.apache.fluss.server.metadata.ServerInfo;
-import org.apache.fluss.server.metrics.group.TestingMetricGroups;
+import org.apache.fluss.server.metrics.group.CoordinatorMetricGroup;
 import org.apache.fluss.server.zk.ZkEpoch;
 
 import org.junit.jupiter.api.Test;
@@ -76,8 +77,15 @@ class CoordinatorEventManagerTest {
                     }
                 };
 
-        CoordinatorEventManager manager =
-                new CoordinatorEventManager(testProcessor, 
TestingMetricGroups.COORDINATOR_METRICS);
+        // Create a fresh metric group per test to avoid gauge name collisions 
with other
+        // tests that share the static TestingMetricGroups.COORDINATOR_METRICS 
instance.
+        // AbstractMetricGroup.addMetric() rejects new gauges when a same-name 
gauge already
+        // exists (keeps the old one), which causes this test to read a stale 
gauge bound to
+        // a different CoordinatorEventManager instance.
+        CoordinatorMetricGroup metricGroup =
+                new CoordinatorMetricGroup(NOPMetricRegistry.INSTANCE, 
"cluster1", "host", "0");
+
+        CoordinatorEventManager manager = new 
CoordinatorEventManager(testProcessor, metricGroup);
         manager.start();
 
         try {
@@ -88,10 +96,7 @@ class CoordinatorEventManagerTest {
                     () -> 
assertThat(metricsUpdateCount.get()).isGreaterThan(0));
 
             Gauge activeTabletServerCount =
-                    (Gauge)
-                            TestingMetricGroups.COORDINATOR_METRICS
-                                    .getMetrics()
-                                    
.get(MetricNames.ACTIVE_TABLET_SERVER_COUNT);
+                    (Gauge) 
metricGroup.getMetrics().get(MetricNames.ACTIVE_TABLET_SERVER_COUNT);
             // The gauge reads the volatile tabletServerCount field which is 
updated
             // after the AccessContextEvent future completes. Use retry to 
handle
             // the brief window between metricsUpdateCount increment (inside 
the
@@ -102,7 +107,7 @@ class CoordinatorEventManagerTest {
                     () -> 
assertThat(activeTabletServerCount.getValue()).isEqualTo(2));
         } finally {
             manager.close();
-            TestingMetricGroups.COORDINATOR_METRICS.close();
+            metricGroup.close();
         }
     }