flink-libraries/flink-gelly/src/test/java/org/apache/flink/graph/library/CommunityDetectionTest.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
 *
 *   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.graph.library;

import org.apache.flink.api.common.typeinfo.TypeHint;
import org.apache.flink.graph.Edge;
import org.apache.flink.graph.Graph;
import org.apache.flink.graph.Vertex;
import org.apache.flink.graph.asm.AsmTestBase;
import org.apache.flink.graph.asm.dataset.ChecksumHashCode;
import org.apache.flink.graph.asm.dataset.ChecksumHashCode.Checksum;
import org.apache.flink.graph.generator.SingletonEdgeGraph;
import org.apache.flink.test.util.TestBaseUtils;
import org.apache.flink.types.IntValue;
import org.apache.flink.types.LongValue;

import org.junit.Test;

import static org.junit.Assert.assertEquals;

/**
 * Tests for {@link CommunityDetection}.
 */
public class CommunityDetectionTest extends AsmTestBase {

	@Test
	public void testWithSimpleGraph() throws Exception {
		Graph<IntValue, Long, Double> result = undirectedSimpleGraph
			.mapVertices(v -> (long) v.getId().getValue(),
				new TypeHint<Vertex<IntValue, Long>>(){}.getTypeInfo())
			.mapEdges(e -> (double) e.getTarget().getValue() + e.getSource().getValue(),
				new TypeHint<Edge<IntValue, Double>>(){}.getTypeInfo())
			.run(new CommunityDetection<>(10, 0.5));

		String expectedResult =
			"(0,3)\n" +
			"(1,5)\n" +
			"(2,5)\n" +
			"(3,3)\n" +
			"(4,5)\n" +
			"(5,5)\n";

		TestBaseUtils.compareResultAsText(result.getVertices().collect(), expectedResult);
	}

	@Test
	public void testWithSingletonEdgeGraph() throws Exception {
		Graph<LongValue, Long, Double> result = new SingletonEdgeGraph(env, 1)
			.generate()
			.mapVertices(v -> v.getId().getValue(),
				new TypeHint<Vertex<LongValue, Long>>(){}.getTypeInfo())
			.mapEdges(e -> 1.0,
				new TypeHint<Edge<LongValue, Double>>(){}.getTypeInfo())
			.run(new CommunityDetection<>(10, 0.5));

		String expectedResult =
			"(0,0)\n" +
			"(1,1)\n";

		TestBaseUtils.compareResultAsText(result.getVertices().collect(), expectedResult);
	}

	@Test
	public void testWithEmptyGraphWithVertices() throws Exception {
		emptyGraphWithVertices
			.mapVertices(v -> 0L,
				new TypeHint<Vertex<LongValue, Long>>(){}.getTypeInfo())
			.mapEdges(e -> 0.0,
				new TypeHint<Edge<LongValue, Double>>(){}.getTypeInfo())
			.run(new CommunityDetection<>(10, 0.5));
	}

	@Test
	public void testWithEmptyGraphWithoutVertices() throws Exception {
		emptyGraphWithoutVertices
			.mapVertices(v -> 0L,
				new TypeHint<Vertex<LongValue, Long>>(){}.getTypeInfo())
			.mapEdges(e -> 0.0,
				new TypeHint<Edge<LongValue, Double>>(){}.getTypeInfo())
			.run(new CommunityDetection<>(10, 0.5));
	}

	@Test
	public void testWithRMatGraph() throws Exception {
		Graph<LongValue, Long, Double> result = undirectedRMatGraph(8, 4)
			.mapVertices(v -> v.getId().getValue(),
				new TypeHint<Vertex<LongValue, Long>>(){}.getTypeInfo())
			.mapEdges(e -> (double) e.getTarget().getValue() - e.getSource().getValue(),
				new TypeHint<Edge<LongValue, Double>>(){}.getTypeInfo())
			.run(new CommunityDetection<>(10, 0.5));

		Checksum checksum = new ChecksumHashCode<Vertex<LongValue, Long>>()
			.run(result.getVertices())
			.execute();

		assertEquals(184, checksum.getCount());
		assertEquals(0x00000000000cdc96L, checksum.getChecksum());
	}
}