mjsax commented on code in PR #13996: URL: https://github.com/apache/kafka/pull/13996#discussion_r1271148006
########## 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); + } + + @Test + public void testMinCostDetectNodeNotInNegativeCycle() { + final Graph<Integer> graph1 = new Graph<>(); + + graph1.addEdge(5, 0, 1, 0, 1); + graph1.addEdge(5, 1, 1, 0, 1); + + graph1.addEdge(0, 2, 1, 1, 0); + graph1.addEdge(0, 3, 1, 1, 0); + graph1.addEdge(0, 4, 1, 10, 1); + + graph1.addEdge(1, 2, 1, 1, 0); + graph1.addEdge(1, 3, 1, 10, 1); + graph1.addEdge(1, 4, 1, 1, 0); + + graph1.addEdge(2, 6, 0, 0, 0); + graph1.addEdge(3, 6, 1, 0, 1); + graph1.addEdge(4, 6, 1, 0, 1); + + graph1.setSourceNode(5); + graph1.setSinkNode(6); + + assertEquals(20, graph1.totalCost()); + + // In this graph, the node we found for negative cycle is 2. However 2 isn't in the negative + // cycle itself. Negative cycle is 1 -> 4 -> 0 -> 3 -> 1 + graph1.solveMinCostFlow(); + assertEquals(2, graph1.totalCost()); + + Map<Integer, Graph<Integer>.Edge> edges = graph1.edges(5); + assertEquals(getEdge(0, 1, 0, 0, 1), edges.get(0)); + assertEquals(getEdge(1, 1, 0, 0, 1), edges.get(1)); + + edges = graph1.edges(0); + assertEquals(getEdge(2, 1, 1, 1, 0), edges.get(2)); + assertEquals(getEdge(3, 1, 1, 0, 1), edges.get(3)); + assertEquals(getEdge(4, 1, 10, 1, 0), edges.get(4)); + + edges = graph1.edges(1); + assertEquals(getEdge(2, 1, 1, 1, 0), edges.get(2)); + assertEquals(getEdge(3, 1, 10, 1, 0), edges.get(3)); + assertEquals(getEdge(4, 1, 1, 0, 1), edges.get(4)); + + edges = graph1.edges(2); + assertEquals(getEdge(6, 0, 0, 0, 0), edges.get(6)); + + edges = graph1.edges(3); + assertEquals(getEdge(6, 1, 0, 0, 1), edges.get(6)); + + edges = graph1.edges(4); + assertEquals(getEdge(6, 1, 0, 0, 1), edges.get(6)); + } + + @Test + public void testDeterministic() { + final List<TestEdge> edgeList = new ArrayList<>(); + edgeList.add(new TestEdge(0, 1, 1, 2, 1)); + edgeList.add(new TestEdge(0, 2, 1, 1, 0)); + edgeList.add(new TestEdge(0, 3, 1, 1, 0)); + edgeList.add(new TestEdge(0, 4, 1, 1, 0)); + edgeList.add(new TestEdge(1, 5, 1, 1, 1)); + edgeList.add(new TestEdge(2, 5, 1, 1, 0)); + edgeList.add(new TestEdge(3, 5, 1, 1, 0)); + edgeList.add(new TestEdge(4, 5, 1, 1, 0)); + + // Test no matter the order of adding edges, min cost flow flows from 0 to 2 and then from 2 to 5 + for (int i = 0; i < 10; i++) { Review Comment: Test should run fast. Don't feel strongly about it. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: jira-unsubscr...@kafka.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
