From 993bca9af479a35ddf3868b2682f2e8ace7d8dc2 Mon Sep 17 00:00:00 2001
From: Xinyuan Lin <xinyual3@uci.edu>
Date: Wed, 29 Apr 2026 23:26:03 -0700
Subject: [PATCH] test(amber): add unit test coverage for WorkflowScheduler
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### What changes were proposed in this PR?

Add `WorkflowSchedulerSpec` covering the public contract of
`WorkflowScheduler`:

- `updateSchedule` populates `getSchedule` and `physicalPlan` from the
  input workflow
- The produced schedule covers every operator in the (post-update)
  physical plan
- `getNextRegions` exhausts the schedule and then returns an empty set
- The union of region sets pulled via `getNextRegions` matches
  `getSchedule.getRegions`

### Any related issues, documentation, discussions?

Closes #4563

### How was this PR tested?

`sbt "WorkflowExecutionService/testOnly org.apache.texera.amber.engine.architecture.controller.WorkflowSchedulerSpec"` — 4/4 tests pass.

### Was this PR authored or co-authored using generative AI tooling?

Generated-by: Claude Code (Claude Opus 4.7)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 .../controller/WorkflowSchedulerSpec.scala    | 103 ++++++++++++++++++
 1 file changed, 103 insertions(+)
 create mode 100644 amber/src/test/scala/org/apache/texera/amber/engine/architecture/controller/WorkflowSchedulerSpec.scala

diff --git a/amber/src/test/scala/org/apache/texera/amber/engine/architecture/controller/WorkflowSchedulerSpec.scala b/amber/src/test/scala/org/apache/texera/amber/engine/architecture/controller/WorkflowSchedulerSpec.scala
new file mode 100644
index 00000000000..ac7358b438f
--- /dev/null
+++ b/amber/src/test/scala/org/apache/texera/amber/engine/architecture/controller/WorkflowSchedulerSpec.scala
@@ -0,0 +1,103 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.texera.amber.engine.architecture.controller
+
+import org.apache.texera.amber.core.workflow.{PortIdentity, WorkflowContext}
+import org.apache.texera.amber.engine.common.virtualidentity.util.CONTROLLER
+import org.apache.texera.amber.engine.e2e.TestUtils.buildWorkflow
+import org.apache.texera.amber.operator.TestOperators
+import org.apache.texera.workflow.LogicalLink
+import org.scalatest.flatspec.AnyFlatSpec
+
+class WorkflowSchedulerSpec extends AnyFlatSpec {
+
+  private def buildHeaderlessCsvKeywordWorkflow() = {
+    val csvOpDesc = TestOperators.headerlessSmallCsvScanOpDesc()
+    val keywordOpDesc = TestOperators.keywordSearchOpDesc("column-1", "Asia")
+    buildWorkflow(
+      List(csvOpDesc, keywordOpDesc),
+      List(
+        LogicalLink(
+          csvOpDesc.operatorIdentifier,
+          PortIdentity(0),
+          keywordOpDesc.operatorIdentifier,
+          PortIdentity(0)
+        )
+      ),
+      new WorkflowContext()
+    )
+  }
+
+  "WorkflowScheduler.updateSchedule" should "populate the schedule and physicalPlan fields" in {
+    val workflow = buildHeaderlessCsvKeywordWorkflow()
+    val scheduler = new WorkflowScheduler(workflow.context, CONTROLLER)
+
+    assert(scheduler.getSchedule == null)
+    assert(scheduler.physicalPlan == null)
+
+    scheduler.updateSchedule(workflow.physicalPlan)
+
+    assert(scheduler.getSchedule != null)
+    assert(scheduler.physicalPlan != null)
+    assert(scheduler.getSchedule.getRegions.nonEmpty)
+  }
+
+  it should "include every workflow operator in some region of the produced schedule" in {
+    val workflow = buildHeaderlessCsvKeywordWorkflow()
+    val scheduler = new WorkflowScheduler(workflow.context, CONTROLLER)
+    scheduler.updateSchedule(workflow.physicalPlan)
+
+    val operatorsInSchedule = scheduler.getSchedule.getRegions
+      .flatMap(_.getOperators.map(_.id.logicalOpId))
+      .toSet
+    val operatorsInPlan = scheduler.physicalPlan.operators.map(_.id.logicalOpId)
+
+    assert(operatorsInPlan.subsetOf(operatorsInSchedule))
+  }
+
+  "WorkflowScheduler.getNextRegions" should "exhaust the schedule and then return an empty set" in {
+    val workflow = buildHeaderlessCsvKeywordWorkflow()
+    val scheduler = new WorkflowScheduler(workflow.context, CONTROLLER)
+    scheduler.updateSchedule(workflow.physicalPlan)
+
+    val pulledLevels = Iterator
+      .continually(scheduler.getNextRegions)
+      .takeWhile(_.nonEmpty)
+      .toList
+
+    assert(pulledLevels.nonEmpty)
+    assert(scheduler.getNextRegions.isEmpty)
+  }
+
+  it should "yield region sets that together cover every region in the schedule" in {
+    val workflow = buildHeaderlessCsvKeywordWorkflow()
+    val scheduler = new WorkflowScheduler(workflow.context, CONTROLLER)
+    scheduler.updateSchedule(workflow.physicalPlan)
+
+    val expectedRegions = scheduler.getSchedule.getRegions.toSet
+    val pulledRegions = Iterator
+      .continually(scheduler.getNextRegions)
+      .takeWhile(_.nonEmpty)
+      .flatten
+      .toSet
+
+    assert(pulledRegions == expectedRegions)
+  }
+}