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Author: Jivan052

src/test/java/com/thealgorithms/backtracking/DijkstraAlgorithmTest.java

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+package com.thealgorithms.backtracking;
+
+
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.*;
+import java.util.*;
+
+class DijkstraTest {
+
+    @Test
+    void testSingleNodeGraph() {
+        Graph graph = new Graph();
+        graph.addEdge(1, 1, 0);
+
+        Dijkstra dijkstra = new Dijkstra();
+        Map<Integer, Integer> distances = dijkstra.findShortestPaths(graph, 1);
+
+        assertEquals(0, (int) distances.get(1));
+    }
+
+    @Test
+    void testSimpleGraph() {
+        Graph graph = new Graph();
+        graph.addEdge(1, 2, 1);
+        graph.addEdge(2, 3, 2);
+        graph.addEdge(1, 3, 4);
+
+        Dijkstra dijkstra = new Dijkstra();
+        Map<Integer, Integer> distances = dijkstra.findShortestPaths(graph, 1);
+
+        assertEquals(0, (int) distances.get(1));
+        assertEquals(1, (int) distances.get(2));
+        assertEquals(3, (int) distances.get(3));
+    }
+
+    @Test
+    void testComplexGraph() {
+        Graph graph = new Graph();
+        graph.addEdge(1, 2, 10);
+        graph.addEdge(1, 3, 5);
+        graph.addEdge(3, 2, 3);
+        graph.addEdge(2, 4, 1);
+        graph.addEdge(3, 4, 9);
+        graph.addEdge(4, 5, 2);
+
+        Dijkstra dijkstra = new Dijkstra();
+        Map<Integer, Integer> distances = dijkstra.findShortestPaths(graph, 1);
+
+        assertEquals(0, (int) distances.get(1));
+        assertEquals(8, (int) distances.get(2));
+        assertEquals(5, (int) distances.get(3));
+        assertEquals(9, (int) distances.get(4));
+        assertEquals(11, (int) distances.get(5));
+    }
+
+    @Test
+    void testDisconnectedGraph() {
+        Graph graph = new Graph();
+        graph.addEdge(1, 2, 5);
+        graph.addEdge(3, 4, 7);
+
+        Dijkstra dijkstra = new Dijkstra();
+        Map<Integer, Integer> distances = dijkstra.findShortestPaths(graph, 1);
+
+        assertEquals(0, (int) distances.get(1));
+        assertEquals(5, (int) distances.get(2));
+        assertNull(distances.get(3)); 
+    }
+
+    @Test
+    void testGraphWithLoops() {
+        Graph graph = new Graph();
+        graph.addEdge(1, 1, 0);  
+        graph.addEdge(1, 2, 2);
+        graph.addEdge(2, 3, 4);
+        graph.addEdge(3, 1, 6);
+
+        Dijkstra dijkstra = new Dijkstra();
+        Map<Integer, Integer> distances = dijkstra.findShortestPaths(graph, 1);
+
+        assertEquals(0, (int) distances.get(1));
+        assertEquals(2, (int) distances.get(2));
+        assertEquals(6, (int) distances.get(3));
+    }
+}