lihaosky commented on code in PR #13996: URL: https://github.com/apache/kafka/pull/13996#discussion_r1271010298
########## streams/src/test/java/org/apache/kafka/streams/processor/internals/assignment/GraphTest.java: ########## @@ -0,0 +1,414 @@ +/* + * 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.kafka.streams.processor.internals.assignment; + +import static org.hamcrest.MatcherAssert.assertThat; +import static org.hamcrest.Matchers.contains; +import static org.junit.jupiter.api.Assertions.assertEquals; +import static org.junit.jupiter.api.Assertions.assertFalse; +import static org.junit.jupiter.api.Assertions.assertNull; +import static org.junit.jupiter.api.Assertions.assertSame; +import static org.junit.jupiter.api.Assertions.assertThrows; +import static org.junit.jupiter.api.Assertions.assertTrue; + +import java.util.ArrayList; +import java.util.Collections; +import java.util.List; +import java.util.Map; +import java.util.Set; +import org.junit.Before; +import org.junit.Test; + +public class GraphTest { + private Graph<Integer> graph; + + @Before + public void setUp() { + /* + * Node 0 and 2 are both connected to node 1 and 3. There's a flow of 1 unit from 0 to 1 and 2 to + * 3. The total cost in this case is 5. Min cost should be 2 by flowing 1 unit from 0 to 3 and 2 + * to 1 + */ + graph = new Graph<>(); + graph.addEdge(0, 1, 1, 3, 1); + graph.addEdge(0, 3, 1, 1, 0); + graph.addEdge(2, 1, 1, 1, 0); + graph.addEdge(2, 3, 1, 2, 1); + graph.addEdge(4, 0, 1, 0, 1); + graph.addEdge(4, 2, 1, 0, 1); + graph.addEdge(1, 5, 1, 0, 1); + graph.addEdge(3, 5, 1, 0, 1); + graph.setSourceNode(4); + graph.setSinkNode(5); + } + + @Test + public void testBasic() { + final Set<Integer> nodes = graph.nodes(); + assertEquals(6, nodes.size()); + assertThat(nodes, contains(0, 1, 2, 3, 4, 5)); + + Map<Integer, Graph<Integer>.Edge> edges = graph.edges(0); + assertEquals(2, edges.size()); + assertEquals(getEdge(1, 1, 3, 0, 1), edges.get(1)); + assertEquals(getEdge(3, 1, 1, 1, 0), edges.get(3)); + + edges = graph.edges(2); + assertEquals(2, edges.size()); + assertEquals(getEdge(1, 1, 1, 1, 0), edges.get(1)); + assertEquals(getEdge(3, 1, 2, 0, 1), edges.get(3)); + + edges = graph.edges(1); + assertEquals(1, edges.size()); + assertEquals(getEdge(5, 1, 0, 0, 1), edges.get(5)); + + edges = graph.edges(3); + assertEquals(1, edges.size()); + assertEquals(getEdge(5, 1, 0, 0, 1), edges.get(5)); + + edges = graph.edges(4); + assertEquals(2, edges.size()); + assertEquals(getEdge(0, 1, 0, 0, 1), edges.get(0)); + assertEquals(getEdge(2, 1, 0, 0, 1), edges.get(2)); + + edges = graph.edges(5); + assertNull(edges); + + assertFalse(graph.isResidualGraph()); + } + + @Test + public void testResidualGraph() { + final Graph<Integer> residualGraph = graph.residualGraph(); + final Graph<Integer> residualGraph1 = residualGraph.residualGraph(); + assertSame(residualGraph1, residualGraph); + + final Set<Integer> nodes = residualGraph.nodes(); + assertEquals(6, nodes.size()); + assertThat(nodes, contains(0, 1, 2, 3, 4, 5)); + + Map<Integer, Graph<Integer>.Edge> edges = residualGraph.edges(0); + assertEquals(3, edges.size()); + assertEquals(getEdge(1, 1, 3, 0, 1), edges.get(1)); + assertEquals(getEdge(3, 1, 1, 1, 0), edges.get(3)); + assertEquals(getEdge(4, 1, 0, 1, 0, false), edges.get(4)); + + edges = residualGraph.edges(2); + assertEquals(3, edges.size()); + assertEquals(getEdge(1, 1, 1, 1, 0), edges.get(1)); + assertEquals(getEdge(3, 1, 2, 0, 1), edges.get(3)); + assertEquals(getEdge(4, 1, 0, 1, 0, false), edges.get(4)); + + edges = residualGraph.edges(1); + assertEquals(3, edges.size()); + assertEquals(getEdge(0, 1, -3, 1, 0, false), edges.get(0)); + assertEquals(getEdge(2, 1, -1, 0, 0, false), edges.get(2)); + assertEquals(getEdge(5, 1, 0, 0, 1), edges.get(5)); + + edges = residualGraph.edges(3); + assertEquals(3, edges.size()); + assertEquals(getEdge(0, 1, -1, 0, 0, false), edges.get(0)); + assertEquals(getEdge(2, 1, -2, 1, 0, false), edges.get(2)); + assertEquals(getEdge(5, 1, 0, 0, 1), edges.get(5)); + + assertTrue(residualGraph.isResidualGraph()); + } + + @Test + public void testInvalidOperation() { + final Graph<Integer> graph1 = new Graph<>(); + Exception exception = assertThrows(IllegalArgumentException.class, () -> graph1.addEdge(0, 1, -1, 0, 0)); + assertEquals("Edge capacity cannot be negative", exception.getMessage()); + + exception = assertThrows(IllegalArgumentException.class, () -> graph1.addEdge(0, 1, 1, 0, 2)); + assertEquals("Edge flow 2 cannot exceed capacity 1", exception.getMessage()); + + graph1.addEdge(0, 1, 1, 1, 1); + exception = assertThrows(IllegalArgumentException.class, () -> graph1.addEdge(1, 0, 1, 0, 0)); + assertEquals("There is already an edge from 0 to 1. Can not add an edge from 1 to 0 since " + + "there will create a cycle between two nodes", exception.getMessage()); + + final Graph<Integer> residualGraph = graph1.residualGraph(); + exception = assertThrows(IllegalStateException.class, residualGraph::solveMinCostFlow); + assertEquals("Should not be residual graph to solve min cost flow", exception.getMessage()); + + } + + @Test + public void testInvalidSource() { + final Graph<Integer> graph1 = new Graph<>(); + graph1.addEdge(0, 1, 1, 1, 0); + graph1.addEdge(1, 2, 1, 1, 0); + graph1.setSourceNode(1); + graph1.setSinkNode(2); + final Exception exception = assertThrows(IllegalStateException.class, graph1::solveMinCostFlow); + assertEquals("Source node 1 shouldn't have input 0", exception.getMessage()); + } + + @Test + public void testInvalidSink() { + final Graph<Integer> graph1 = new Graph<>(); + graph1.addEdge(0, 1, 1, 1, 0); + graph1.addEdge(1, 2, 1, 1, 0); + graph1.setSourceNode(0); + graph1.setSinkNode(1); + final Exception exception = assertThrows(IllegalStateException.class, graph1::solveMinCostFlow); + assertEquals("Sink node 1 shouldn't have output", exception.getMessage()); + } + + @Test + public void testInvalidFlow() { + final Graph<Integer> graph1 = new Graph<>(); + graph1.addEdge(0, 1, 1, 1, 1); + graph1.addEdge(0, 2, 2, 1, 2); + graph1.addEdge(1, 3, 1, 1, 1); + graph1.addEdge(2, 3, 2, 1, 0); // Missing flow from 2 to 3 + graph1.setSourceNode(0); + graph1.setSinkNode(3); + final Exception exception = assertThrows(IllegalStateException.class, graph1::solveMinCostFlow); + assertEquals("Input flow for node 2 is 2 which doesn't match output flow 0", exception.getMessage()); + } + + @Test + public void testMissingSource() { + final Graph<Integer> graph1 = new Graph<>(); + graph1.addEdge(0, 1, 1, 1, 1); + graph1.addEdge(0, 2, 2, 1, 2); + graph1.addEdge(1, 3, 1, 1, 1); + graph1.addEdge(2, 3, 2, 1, 2); + graph1.setSinkNode(3); + final Exception exception = assertThrows(IllegalStateException.class, graph1::solveMinCostFlow); + assertEquals("Output flow for source null is null which doesn't match input flow 3 for sink 3", + exception.getMessage()); + } + + @Test + public void testDisconnectedGraph() { + final Graph<Integer> graph1 = new Graph<>(); + graph1.addEdge(0, 1, 1, 1, 1); + graph1.addEdge(2, 3, 2, 1, 2); + graph1.setSourceNode(0); + graph1.setSinkNode(1); + final Exception exception = assertThrows(IllegalStateException.class, graph1::solveMinCostFlow); + assertEquals("Input flow for node 3 is 2 which doesn't match output flow null", + exception.getMessage()); + } + + @Test + public void testDisconnectedGraphCrossSourceSink() { + final Graph<Integer> graph1 = new Graph<>(); + graph1.addEdge(0, 1, 1, 1, 1); + graph1.addEdge(2, 3, 2, 1, 2); + graph1.setSourceNode(0); + graph1.setSinkNode(3); + final Exception exception = assertThrows(IllegalStateException.class, graph1::solveMinCostFlow); + assertEquals("Input flow for node 1 is 1 which doesn't match output flow null", + exception.getMessage()); + } + + @Test + public void testJustSourceSink() { + final Graph<Integer> graph1 = new Graph<>(); + graph1.addEdge(0, 1, 1, 1, 1); + graph1.setSourceNode(0); + graph1.setSinkNode(1); + graph1.solveMinCostFlow(); + assertEquals(1, graph1.totalCost()); + } + + @Test + public void testMinCostFlow() { + // Original graph, flow from 0 to 1 and 2 to 3 + Map<Integer, Graph<Integer>.Edge> edges = graph.edges(0); + Graph<Integer>.Edge edge = edges.get(1); + assertEquals(1, edge.flow); + assertEquals(0, edge.residualFlow); + + edge = edges.get(3); + assertEquals(0, edge.flow); + assertEquals(1, edge.residualFlow); + + edges = graph.edges(2); + edge = edges.get(3); + assertEquals(1, edge.flow); + assertEquals(0, edge.residualFlow); + + edge = edges.get(1); + assertEquals(0, edge.flow); + assertEquals(1, edge.residualFlow); + + assertEquals(5, graph.totalCost()); + + graph.solveMinCostFlow(); + + assertEquals(2, graph.totalCost()); + + edges = graph.edges(0); + assertEquals(2, edges.size()); + + // No flow from 0 to 1 + edge = edges.get(1); + assertEquals(0, edge.flow); + assertEquals(1, edge.residualFlow); + + // Flow from 0 to 3 now + edge = edges.get(3); + assertEquals(1, edge.flow); + assertEquals(0, edge.residualFlow); + + edges = graph.edges(2); + assertEquals(2, edges.size()); + + // No flow from 2 to 3 + edge = edges.get(3); + assertEquals(0, edge.flow); + assertEquals(1, edge.residualFlow); + + // Flow from 2 to 1 now + edge = edges.get(1); + assertEquals(1, edge.flow); + assertEquals(0, edge.residualFlow); + } Review Comment: 0->3 flow is checked on line 269? -- This is an automated message from the Apache Git Service. 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