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/*
* Copyright (C) 2016 The Guava Authors
*
* Licensed 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 com.google.common.graph;
import static com.google.common.truth.Truth.assertThat;
import static org.junit.Assert.assertThrows;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.testing.EqualsTester;
import java.util.Collection;
import java.util.Set;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;
/** Tests for {@link EndpointPair} and {@link Graph#edges()}. */
@RunWith(JUnit4.class)
public final class EndpointPairTest {
private static final Integer N0 = 0;
private static final Integer N1 = 1;
private static final Integer N2 = 2;
private static final Integer N3 = 3;
private static final Integer N4 = 4;
private static final String E12 = "1-2";
private static final String E12_A = "1-2a";
private static final String E21 = "2-1";
private static final String E13 = "1-3";
private static final String E44 = "4-4";
// Test for EndpointPair class
@Test
public void testOrderedEndpointPair() {
EndpointPair<String> ordered = EndpointPair.ordered("source", "target");
assertThat(ordered.isOrdered()).isTrue();
assertThat(ordered).containsExactly("source", "target").inOrder();
assertThat(ordered.source()).isEqualTo("source");
assertThat(ordered.target()).isEqualTo("target");
assertThat(ordered.nodeU()).isEqualTo("source");
assertThat(ordered.nodeV()).isEqualTo("target");
assertThat(ordered.adjacentNode("source")).isEqualTo("target");
assertThat(ordered.adjacentNode("target")).isEqualTo("source");
assertThat(ordered.toString()).isEqualTo("<source -> target>");
}
@Test
public void testUnorderedEndpointPair() {
EndpointPair<String> unordered = EndpointPair.unordered("chicken", "egg");
assertThat(unordered.isOrdered()).isFalse();
assertThat(unordered).containsExactly("chicken", "egg");
assertThat(ImmutableSet.of(unordered.nodeU(), unordered.nodeV()))
.containsExactly("chicken", "egg");
assertThat(unordered.adjacentNode(unordered.nodeU())).isEqualTo(unordered.nodeV());
assertThat(unordered.adjacentNode(unordered.nodeV())).isEqualTo(unordered.nodeU());
assertThat(unordered.toString()).contains("chicken");
assertThat(unordered.toString()).contains("egg");
}
@Test
public void testSelfLoop() {
EndpointPair<String> unordered = EndpointPair.unordered("node", "node");
assertThat(unordered.isOrdered()).isFalse();
assertThat(unordered).containsExactly("node", "node");
assertThat(unordered.nodeU()).isEqualTo("node");
assertThat(unordered.nodeV()).isEqualTo("node");
assertThat(unordered.adjacentNode("node")).isEqualTo("node");
assertThat(unordered.toString()).isEqualTo("[node, node]");
}
@Test
public void testAdjacentNode_nodeNotIncident() {
ImmutableList<MutableNetwork<Integer, String>> testNetworks =
ImmutableList.of(
NetworkBuilder.directed().<Integer, String>build(),
NetworkBuilder.undirected().<Integer, String>build());
for (MutableNetwork<Integer, String> network : testNetworks) {
network.addEdge(1, 2, "1-2");
EndpointPair<Integer> endpointPair = network.incidentNodes("1-2");
assertThrows(IllegalArgumentException.class, () -> endpointPair.adjacentNode(3));
}
}
@Test
public void testEquals() {
EndpointPair<String> ordered = EndpointPair.ordered("a", "b");
EndpointPair<String> orderedMirror = EndpointPair.ordered("b", "a");
EndpointPair<String> unordered = EndpointPair.unordered("a", "b");
EndpointPair<String> unorderedMirror = EndpointPair.unordered("b", "a");
new EqualsTester()
.addEqualityGroup(ordered)
.addEqualityGroup(orderedMirror)
.addEqualityGroup(unordered, unorderedMirror)
.testEquals();
}
// Tests for Graph.edges() and Network.asGraph().edges() methods
// TODO(user): Move these to a more appropriate location in the test suite.
@Test
public void endpointPair_directedGraph() {
MutableGraph<Integer> directedGraph = GraphBuilder.directed().allowsSelfLoops(true).build();
directedGraph.addNode(N0);
directedGraph.putEdge(N1, N2);
directedGraph.putEdge(N2, N1);
directedGraph.putEdge(N1, N3);
directedGraph.putEdge(N4, N4);
containsExactlySanityCheck(
directedGraph.edges(),
EndpointPair.ordered(N1, N2),
EndpointPair.ordered(N2, N1),
EndpointPair.ordered(N1, N3),
EndpointPair.ordered(N4, N4));
}
@Test
public void endpointPair_undirectedGraph() {
MutableGraph<Integer> undirectedGraph = GraphBuilder.undirected().allowsSelfLoops(true).build();
undirectedGraph.addNode(N0);
undirectedGraph.putEdge(N1, N2);
undirectedGraph.putEdge(N2, N1); // does nothing
undirectedGraph.putEdge(N1, N3);
undirectedGraph.putEdge(N4, N4);
containsExactlySanityCheck(
undirectedGraph.edges(),
EndpointPair.unordered(N1, N2),
EndpointPair.unordered(N1, N3),
EndpointPair.unordered(N4, N4));
}
@Test
public void endpointPair_directedNetwork() {
MutableNetwork<Integer, String> directedNetwork =
NetworkBuilder.directed().allowsSelfLoops(true).build();
directedNetwork.addNode(N0);
directedNetwork.addEdge(N1, N2, E12);
directedNetwork.addEdge(N2, N1, E21);
directedNetwork.addEdge(N1, N3, E13);
directedNetwork.addEdge(N4, N4, E44);
containsExactlySanityCheck(
directedNetwork.asGraph().edges(),
EndpointPair.ordered(N1, N2),
EndpointPair.ordered(N2, N1),
EndpointPair.ordered(N1, N3),
EndpointPair.ordered(N4, N4));
}
@Test
public void endpointPair_undirectedNetwork() {
MutableNetwork<Integer, String> undirectedNetwork =
NetworkBuilder.undirected().allowsParallelEdges(true).allowsSelfLoops(true).build();
undirectedNetwork.addNode(N0);
undirectedNetwork.addEdge(N1, N2, E12);
undirectedNetwork.addEdge(N2, N1, E12_A); // adds parallel edge, won't be in Graph edges
undirectedNetwork.addEdge(N1, N3, E13);
undirectedNetwork.addEdge(N4, N4, E44);
containsExactlySanityCheck(
undirectedNetwork.asGraph().edges(),
EndpointPair.unordered(N1, N2),
EndpointPair.unordered(N1, N3),
EndpointPair.unordered(N4, N4));
}
@Test
public void endpointPair_unmodifiableView() {
MutableGraph<Integer> directedGraph = GraphBuilder.directed().build();
Set<EndpointPair<Integer>> edges = directedGraph.edges();
directedGraph.putEdge(N1, N2);
containsExactlySanityCheck(edges, EndpointPair.ordered(N1, N2));
directedGraph.putEdge(N2, N1);
containsExactlySanityCheck(edges, EndpointPair.ordered(N1, N2), EndpointPair.ordered(N2, N1));
directedGraph.removeEdge(N1, N2);
directedGraph.removeEdge(N2, N1);
containsExactlySanityCheck(edges);
assertThrows(
UnsupportedOperationException.class, () -> edges.add(EndpointPair.ordered(N1, N2)));
}
@Test
public void endpointPair_undirected_contains() {
MutableGraph<Integer> undirectedGraph = GraphBuilder.undirected().allowsSelfLoops(true).build();
undirectedGraph.putEdge(N1, N1);
undirectedGraph.putEdge(N1, N2);
Set<EndpointPair<Integer>> edges = undirectedGraph.edges();
assertThat(edges).hasSize(2);
assertThat(edges).contains(EndpointPair.unordered(N1, N1));
assertThat(edges).contains(EndpointPair.unordered(N1, N2));
assertThat(edges).contains(EndpointPair.unordered(N2, N1)); // equal to unordered(N1, N2)
// ordered endpoints not compatible with undirected graph
assertThat(edges).doesNotContain(EndpointPair.ordered(N1, N2));
assertThat(edges).doesNotContain(EndpointPair.unordered(N2, N2)); // edge not present
assertThat(edges).doesNotContain(EndpointPair.unordered(N3, N4)); // nodes not in graph
}
@Test
public void endpointPair_directed_contains() {
MutableGraph<Integer> directedGraph = GraphBuilder.directed().allowsSelfLoops(true).build();
directedGraph.putEdge(N1, N1);
directedGraph.putEdge(N1, N2);
Set<EndpointPair<Integer>> edges = directedGraph.edges();
assertThat(edges).hasSize(2);
assertThat(edges).contains(EndpointPair.ordered(N1, N1));
assertThat(edges).contains(EndpointPair.ordered(N1, N2));
// unordered endpoints not OK for directed graph (undefined behavior)
assertThat(edges).doesNotContain(EndpointPair.unordered(N1, N2));
assertThat(edges).doesNotContain(EndpointPair.ordered(N2, N1)); // wrong order
assertThat(edges).doesNotContain(EndpointPair.ordered(N2, N2)); // edge not present
assertThat(edges).doesNotContain(EndpointPair.ordered(N3, N4)); // nodes not in graph
}
private static void containsExactlySanityCheck(Collection<?> collection, Object... varargs) {
assertThat(collection).hasSize(varargs.length);
for (Object obj : varargs) {
assertThat(collection).contains(obj);
}
assertThat(collection).containsExactly(varargs);
}
}
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