[FLINK-11084]Add tests

flink-streaming-java/src/test/java/org/apache/flink/streaming/api/datastream/ConsecutiveSplitSelectTest.java

@@ -0,0 +1,92 @@
+/*
+ * 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.flink.streaming.api.datastream;
+
+import org.apache.flink.streaming.api.collector.selector.OutputSelector;
+import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
+import org.apache.flink.streaming.api.functions.sink.DiscardingSink;
+
+import org.apache.commons.collections.IteratorUtils;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Test the {@link OutputSelector} for consecutive split and select.
+ */
+public class ConsecutiveSplitSelectTest {
+
+	@Test
+	public void testConsecutiveSplitSelect() {
+		StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
+		DataStream<String> dataStream = env.fromElements("a1", "a2");
+
+		SplitStream<String> splitStream1 = dataStream.split(new OutputSelector<String>() {
+			@Override public Iterable<String> select(String value) {
+				List<String> output = new ArrayList<>(1);
+				if (value.equals("a1")) {
+					output.add("name1");
+				} else {
+					output.add("name2");
+				}
+				return output;
+			}
+		});
+		SplitStream<String> splitStream2 = splitStream1.select("name1").split(new OutputSelector<String>() {
+			@Override public Iterable<String> select(String value) {
+				List<String> output = new ArrayList<>(1);
+				if (value.equals("a1")) {
+					output.add("name4");
+				} else {
+					output.add("name5");
+				}
+				return output;
+			}
+		});
+		splitStream1.addSink(new DiscardingSink<>());
+		splitStream2.addSink(new DiscardingSink<>());
+
+		List<OutputSelector<?>> outputSelectors = env.getStreamGraph().getStreamNode(1).getOutputSelectors();
+		OutputSelector<String> outputSelector1 = (OutputSelector<String>) outputSelectors.get(0);
+		OutputSelector<String> outputSelector2 = (OutputSelector<String>) outputSelectors.get(1);
+
+		List<String> actualResult = IteratorUtils.toList(outputSelector1.select("a1").iterator());
+		List<String> expectedResult = new ArrayList<>();
+		expectedResult.add("name1");
+		validateAndCleanUpTwoList(actualResult, expectedResult);
+
+		actualResult = IteratorUtils.toList(outputSelector2.select("a1").iterator());
+		expectedResult.add("name4");
+		validateAndCleanUpTwoList(actualResult, expectedResult);
+
+		actualResult = IteratorUtils.toList(outputSelector1.select("a2").iterator());
+		expectedResult.add("name2");
+		validateAndCleanUpTwoList(actualResult, expectedResult);
+
+		actualResult = IteratorUtils.toList(outputSelector2.select("a2").iterator());
+		validateAndCleanUpTwoList(actualResult, expectedResult);
+	}
+
+	private void validateAndCleanUpTwoList(List<String> actualResult, List<String> expectedResult) {
+		Assert.assertArrayEquals(actualResult.toArray(), expectedResult.toArray());
+		actualResult.clear();
+		expectedResult.clear();
+	}
+}