lang/java/avro/src/test/java/org/apache/avro/TestUnionSelfReference.java

/*
 * 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
 *
 *     https://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.avro;

import org.slf4j.LoggerFactory;

import static org.junit.Assert.*;

import org.apache.avro.Schema.Field;
import org.apache.avro.Schema.Type;
import org.junit.Test;
import org.slf4j.Logger;

public class TestUnionSelfReference {
  /** The logger for TestUnionSelfReference */
  @SuppressWarnings("unused")
  private static final Logger LOG = LoggerFactory.getLogger(TestUnionSelfReference.class);

  private static final String SIMPLE_BINARY_TREE = "{" + "    \"namespace\": \"tree\"," + "    \"type\": \"record\","
      + "    \"name\": \"Node\"," + "    \"fields\": [" + "      {" + "        \"name\": \"left\","
      + "        \"type\": [" + "          \"null\"," + "          {" + "            \"type\": \"Node\"" + "          }"
      + "        ]," + "        \"default\": null" + "      }," + "      {" + "        \"name\": \"right\","
      + "        \"type\": [" + "          \"null\"," + "          {" + "            \"type\": \"Node\"" + "          }"
      + "        ]," + "        \"default\": null" + "      }" + "    ]" + "  }";

  private static final String THREE_TYPE_UNION = "{" + "    \"namespace\": \"tree\"," + "    \"type\": \"record\","
      + "    \"name\": \"Node\"," + "    \"fields\": [" + "      {" + "        \"name\": \"left\","
      + "        \"type\": [" + "          \"null\"," + "          \"string\"," + "          {"
      + "            \"type\": \"Node\"" + "          }" + "        ]," + "        \"default\": null" + "      },"
      + "      {" + "        \"name\": \"right\"," + "        \"type\": [" + "          \"null\","
      + "          \"string\"," + "          {" + "            \"type\": \"Node\"" + "          }" + "        ],"
      + "        \"default\": null" + "      }" + "    ]" + "  }";

  @Test
  public void testSelfReferenceInUnion() {
    Schema schema = new Schema.Parser().parse(SIMPLE_BINARY_TREE);
    Field leftField = schema.getField("left");
    assertEquals(JsonProperties.NULL_VALUE, leftField.defaultVal());
    final Schema leftFieldSchema = leftField.schema();
    assertEquals(Type.UNION, leftFieldSchema.getType());
    assertEquals("null", leftFieldSchema.getTypes().get(0).getName());
    assertEquals("Node", leftFieldSchema.getTypes().get(1).getName());

    Field rightField = schema.getField("right");
    assertEquals(JsonProperties.NULL_VALUE, rightField.defaultVal());
    final Schema rightFieldSchema = rightField.schema();
    assertEquals(Type.UNION, rightFieldSchema.getType());
    assertEquals("null", rightFieldSchema.getTypes().get(0).getName());
    assertEquals("Node", rightFieldSchema.getTypes().get(1).getName());
  }

  @Test
  public void testSelfReferenceInThreeUnion() {
    Schema schema = new Schema.Parser().parse(THREE_TYPE_UNION);
    Field leftField = schema.getField("left");
    assertEquals(JsonProperties.NULL_VALUE, leftField.defaultVal());
    final Schema leftFieldSchema = leftField.schema();
    assertEquals(Type.UNION, leftFieldSchema.getType());
    assertEquals("null", leftFieldSchema.getTypes().get(0).getName());
    assertEquals("string", leftFieldSchema.getTypes().get(1).getName());
    assertEquals("Node", leftFieldSchema.getTypes().get(2).getName());

    Field rightField = schema.getField("right");
    assertEquals(JsonProperties.NULL_VALUE, rightField.defaultVal());
    final Schema rightFieldSchema = rightField.schema();
    assertEquals(Type.UNION, rightFieldSchema.getType());
    assertEquals("null", rightFieldSchema.getTypes().get(0).getName());
    assertEquals("string", rightFieldSchema.getTypes().get(1).getName());
    assertEquals("Node", rightFieldSchema.getTypes().get(2).getName());
  }

}