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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.container.di.componentgraph.cycle;
import org.junit.jupiter.api.Test;
import java.util.List;
import static com.yahoo.container.di.componentgraph.cycle.CycleFinderTest.Vertices.A;
import static com.yahoo.container.di.componentgraph.cycle.CycleFinderTest.Vertices.B;
import static com.yahoo.container.di.componentgraph.cycle.CycleFinderTest.Vertices.C;
import static com.yahoo.container.di.componentgraph.cycle.CycleFinderTest.Vertices.D;
import static org.junit.jupiter.api.Assertions.assertTrue;
/**
* @author gjoranv
*/
public class CycleFinderTest {
enum Vertices {A, B, C, D}
@Test
void graph_without_cycles_returns_no_cycle() {
var graph = new Graph<Vertices>();
graph.edge(A, B);
graph.edge(B, C);
graph.edge(A, C);
graph.edge(D, A);
var cycleFinder = new CycleFinder<>(graph);
assertTrue(cycleFinder.findCycle().isEmpty());
}
@Test
void graph_with_cycle_returns_cycle() {
var graph = new Graph<Vertices>();
graph.edge(A, B);
graph.edge(B, C);
graph.edge(C, A);
var cycleFinder = new CycleFinder<>(graph);
assertTrue(cycleFinder.findCycle().containsAll(List.of(A, B, C, A)));
}
@Test
void graph_with_self_referencing_vertex_returns_cycle() {
var graph = new Graph<Vertices>();
graph.edge(A, A);
var cycleFinder = new CycleFinder<>(graph);
assertTrue(cycleFinder.findCycle().containsAll(List.of(A, A)));
}
@Test
void leading_nodes_are_stripped_from_cycle() {
var graph = new Graph<Vertices>();
graph.edge(A, B);
graph.edge(B, C);
graph.edge(C, B);
var cycleFinder = new CycleFinder<>(graph);
assertTrue(cycleFinder.findCycle().containsAll(List.of(B, C, B)));
}
@Test
void findCycle_is_idempotent_with_cycle() {
var graph = new Graph<Vertices>();
graph.edge(A, A);
var cycleFinder = new CycleFinder<>(graph);
assertTrue(cycleFinder.findCycle().containsAll(List.of(A, A)));
assertTrue(cycleFinder.findCycle().containsAll(List.of(A, A)));
}
@Test
void findCycle_is_idempotent_without_cycle() {
var graph = new Graph<Vertices>();
graph.edge(A, B);
var cycleFinder = new CycleFinder<>(graph);
assertTrue(cycleFinder.findCycle().isEmpty());
assertTrue(cycleFinder.findCycle().isEmpty());
}
}
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