Flink: add append capability to dynamic iceberg sink (#14526)

flink/v2.1/flink/src/test/java/org/apache/iceberg/flink/sink/dynamic/TestDynamicCommitter.java

@@ -591,6 +591,71 @@ void testTableBranchAtomicCommitWithFailures() throws Exception {
                 .build());
   }
 
+  @Test
+  void testCommitDeltaTxnWithAppendFiles() throws Exception {
+    Table table = catalog.loadTable(TableIdentifier.of(TABLE1));
+    assertThat(table.snapshots()).isEmpty();
+
+    DynamicWriteResultAggregator aggregator =
+        new DynamicWriteResultAggregator(CATALOG_EXTENSION.catalogLoader(), cacheMaximumSize);
+    OneInputStreamOperatorTestHarness aggregatorHarness =
+        new OneInputStreamOperatorTestHarness(aggregator);
+    aggregatorHarness.open();
+
+    WriteTarget writeTarget1 =
+        new WriteTarget(TABLE1, "branch1", 42, 0, true, Sets.newHashSet(1, 2));
+    WriteTarget writeTarget2 = new WriteTarget(TABLE1, "branch1", 23, 0, true, Sets.newHashSet());
+
+    WriteResult writeResult1 = WriteResult.builder().addDataFiles(DATA_FILE).build();
+    WriteResult writeResult2 = WriteResult.builder().addDataFiles(DATA_FILE_2).build();
+
+    final String jobId = JobID.generate().toHexString();
+    final String operatorId = new OperatorID().toHexString();
+    final int checkpointId = 1;
+
+    byte[] deltaManifest1 =
+        aggregator.writeToManifest(
+            writeTarget1,
+            Sets.newHashSet(new DynamicWriteResult(writeTarget1, writeResult1)),
+            checkpointId);
+
+    CommitRequest<DynamicCommittable> commitRequest1 =
+        new MockCommitRequest<>(
+            new DynamicCommittable(writeTarget1, deltaManifest1, jobId, operatorId, checkpointId));
+
+    byte[] deltaManifest2 =
+        aggregator.writeToManifest(
+            writeTarget2,
+            Sets.newHashSet(new DynamicWriteResult(writeTarget2, writeResult2)),
+            checkpointId);
+
+    CommitRequest<DynamicCommittable> commitRequest2 =
+        new MockCommitRequest<>(
+            new DynamicCommittable(writeTarget2, deltaManifest2, jobId, operatorId, checkpointId));
+
+    boolean overwriteMode = false;
+    int workerPoolSize = 1;
+    String sinkId = "sinkId";
+    UnregisteredMetricsGroup metricGroup = new UnregisteredMetricsGroup();
+    DynamicCommitterMetrics committerMetrics = new DynamicCommitterMetrics(metricGroup);
+    DynamicCommitter dynamicCommitter =
+        new DynamicCommitter(
+            CATALOG_EXTENSION.catalog(),
+            Maps.newHashMap(),
+            overwriteMode,
+            workerPoolSize,
+            sinkId,
+            committerMetrics);
+
+    dynamicCommitter.commit(Sets.newHashSet(commitRequest1, commitRequest2));
+
+    table.refresh();
+    assertThat(table.snapshots()).hasSize(1);
+
+    Snapshot snapshot = Iterables.getFirst(table.snapshots(), null);
+    assertThat(snapshot.operation()).isEqualTo("append");
+  }
+
   @Test
   void testReplacePartitions() throws Exception {
     Table table1 = catalog.loadTable(TableIdentifier.of(TABLE1));