[Backport 2.x] Transform pipeline aggr test

src/test/kotlin/org/opensearch/indexmanagement/transform/TransformRunnerIT.kt

@@ -27,9 +27,11 @@ import org.opensearch.script.ScriptType
 import org.opensearch.search.aggregations.AggregationBuilders
 import org.opensearch.search.aggregations.AggregatorFactories
 import org.opensearch.search.aggregations.metrics.ScriptedMetricAggregationBuilder
+import org.opensearch.search.aggregations.pipeline.BucketScriptPipelineAggregationBuilder
 import java.lang.Integer.min
 import java.time.Instant
 import java.time.temporal.ChronoUnit
+import kotlin.test.assertFailsWith
 
 class TransformRunnerIT : TransformRestTestCase() {
 
@@ -688,6 +690,42 @@ class TransformRunnerIT : TransformRestTestCase() {
         assertTrue("Expected failure message to be present", !metadata.failureReason.isNullOrBlank())
     }
 
+    fun `test transform with invalid pipeline aggregation triggering search failure`() {
+        assertFailsWith(IllegalArgumentException::class, "Bucket-script aggregation must fail!") {
+            validateSourceIndex("transform-source-index")
+
+            val aggregatorFactories = AggregatorFactories.builder()
+            aggregatorFactories.addPipelineAggregator(
+                BucketScriptPipelineAggregationBuilder(
+                    "test_pipeline_aggregation",
+                    Script("1")
+                )
+            )
+
+            val transform = Transform(
+                id = "id_17",
+                schemaVersion = 1L,
+                enabled = true,
+                enabledAt = Instant.now(),
+                updatedAt = Instant.now(),
+                jobSchedule = IntervalSchedule(Instant.now(), 1, ChronoUnit.MINUTES),
+                description = "test transform",
+                metadataId = null,
+                sourceIndex = "transform-source-index",
+                targetIndex = "transform-target-index",
+                roles = emptyList(),
+                pageSize = 1,
+                groups = listOf(
+                    Terms(sourceField = "store_and_fwd_flag", targetField = "flag"),
+                    Histogram(sourceField = "passenger_count", targetField = "count", interval = 2.0),
+                    DateHistogram(sourceField = "tpep_pickup_datetime", targetField = "date", fixedInterval = "1d")
+                ),
+                aggregations = aggregatorFactories
+            ).let { createTransform(it, it.id) }
+            updateTransformStartTime(transform)
+        }
+    }
+
     fun `test transform with data stream`() {
         // Create a data stream.
         val dataStreamName = "transform-data-stream"