Fix flaky rollup test by stopping jobs before index cleanup

The test was flaky because rollup job coroutines continued running after
test cleanup, causing a race condition where the config index was recreated
with incorrect dynamic mappings.

Root cause:
- Tests create enabled rollups -> JobScheduler schedules them
- RollupRunner.runJob() launches coroutines via launch {}
- Test @after wipes indices
- BUT coroutines are still running in background
- Coroutines write metadata AFTER indices wiped
- Index auto-creates with wrong dynamic mappings (long vs date)
- Next test fails with mapping conflict on rollup_metadata.continuous.next_window_end_time

Signed-off-by: bowenlan-amzn <bowenlan23@gmail.com>

Author: bowenlan-amzn

src/test/kotlin/org/opensearch/indexmanagement/rollup/RollupRestTestCase.kt

@@ -49,7 +49,7 @@ abstract class RollupRestTestCase : IndexManagementRestTestCase() {
 
     @After
     @Suppress("UNCHECKED_CAST")
-    fun KillAllCancallableRunningTasks() {
+    fun killAllCancellableRunningTasks() {
         client().makeRequest("POST", "_tasks/_cancel?actions=*")
         waitFor {
             val response = client().makeRequest("GET", "_tasks")
@@ -68,21 +68,27 @@ abstract class RollupRestTestCase : IndexManagementRestTestCase() {
     }
 
     @Suppress("UNCHECKED_CAST")
-    fun waitForCancallableTasksToFinish() {
-        waitFor {
-            val response = client().makeRequest("GET", "_tasks")
-            val nodes = response.asMap()["nodes"] as Map<String, Any?>
-            var hasCancallableRunningTasks = false
-            nodes.forEach {
-                val tasks = (it.value as Map<String, Any?>)["tasks"] as Map<String, Any?>
-                tasks.forEach { e ->
-                    if ((e.value as Map<String, Any?>)["cancellable"] as Boolean) {
-                        hasCancallableRunningTasks = true
-                        logger.info("cancellable task running: ${e.key}")
+    protected fun stopAllRollupJobs() {
+        try {
+            val response = client().makeRequest("GET", "$ROLLUP_JOBS_BASE_URI?size=1000")
+            val rollupsList = response.asMap()["rollups"] as? List<Map<String, Any?>> ?: emptyList()
+
+            rollupsList.forEach { rollupMap ->
+                val rollupObj = rollupMap["rollup"] as? Map<String, Any?> ?: return@forEach
+                val id = rollupMap["_id"] as? String ?: return@forEach
+                val enabled = rollupObj["enabled"] as? Boolean ?: false
+
+                if (enabled) {
+                    try {
+                        client().makeRequest("POST", "$ROLLUP_JOBS_BASE_URI/$id/_stop")
+                        logger.debug("Stopped rollup job during test cleanup: $id")
+                    } catch (e: Exception) {
+                        logger.debug("Failed to stop rollup $id during cleanup: ${e.message}")
                     }
                 }
             }
-            assertFalse(hasCancallableRunningTasks)
+        } catch (e: Exception) {
+            logger.warn("Error stopping rollup jobs during test cleanup", e)
         }
     }
 

src/test/kotlin/org/opensearch/indexmanagement/rollup/resthandler/RollupRestAPITestCase.kt

@@ -11,6 +11,14 @@ import org.opensearch.indexmanagement.rollup.RollupRestTestCase
 abstract class RollupRestAPITestCase : RollupRestTestCase() {
     @After
     fun clearIndicesAfterEachTest() {
+        // Stop all rollup jobs first to prevent new executions and allow running coroutines to complete
+        stopAllRollupJobs()
+
+        // Wait for in-flight job executions to complete their metadata writes
+        // This prevents race condition where coroutines recreate config index after wipeAllIndices()
+        Thread.sleep(2000)
+
+
         // For API tests, flaky could happen if config index not deleted
         // metadata creation could cause the mapping to be auto set to
         //  a wrong type, namely, [rollup_metadata.continuous.next_window_end_time] to long