--- /dev/null
+/*
+ * Copyright 2015 Decebal Suiu
+ *
+ * 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 org.pf4j.util;
+
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+/**
+ * @author Decebal Suiu
+ */
+public class DirectedGraphTest {
+
+ private static DirectedGraph<Character> graph;
+
+ @BeforeAll
+ public static void setUp() {
+ graph = new DirectedGraph<>();
+
+ // add vertex
+ graph.addVertex('A');
+ graph.addVertex('B');
+ graph.addVertex('C');
+ graph.addVertex('D');
+ graph.addVertex('E');
+ graph.addVertex('F');
+ graph.addVertex('G');
+
+ // add edges
+ graph.addEdge('A', 'B');
+ graph.addEdge('B', 'C');
+ graph.addEdge('B', 'F');
+ graph.addEdge('D', 'E');
+ graph.addEdge('F', 'G');
+ }
+
+ @Test
+ public void reverseTopologicalSort() {
+ List<Character> result = graph.reverseTopologicalSort();
+ List<Character> expected = Arrays.asList('C', 'G', 'F', 'B', 'A', 'E', 'D');
+ assertEquals(expected, result);
+ }
+
+ @Test
+ public void topologicalSort() {
+ List<Character> result = graph.topologicalSort();
+ List<Character> expected = Arrays.asList('D', 'E', 'A', 'B', 'F', 'G', 'C');
+ assertEquals(expected, result);
+ }
+
+ @Test
+ public void inDegree() {
+ Map<Character, Integer> result = graph.inDegree();
+ Map<Character, Integer> expected = new HashMap<>(7);
+ expected.put('A', 0);
+ expected.put('B', 1);
+ expected.put('C', 1);
+ expected.put('D', 0);
+ expected.put('E', 1);
+ expected.put('F', 1);
+ expected.put('G', 1);
+ assertEquals(expected, result);
+ }
+
+ @Test
+ public void outDegree() {
+ Map<Character, Integer> result = graph.outDegree();
+ Map<Character, Integer> expected = new HashMap<>(7);
+ expected.put('A', 1);
+ expected.put('B', 2);
+ expected.put('C', 0);
+ expected.put('D', 1);
+ expected.put('E', 0);
+ expected.put('F', 1);
+ expected.put('G', 0);
+ assertEquals(expected, result);
+ }
+
+}