Update BridgesTest.java

Author: rajattiwariind

src/test/java/com/thealgorithms/graph/BridgesTest.java

@@ -48,6 +48,13 @@ void testEmptyGraph() {
         assertEquals(0, result.size());
     }
 
+    @Test
+    void testZeroVertices() {
+        List<int[]> result = Bridges.findBridges(0, new int[0][]);
+
+        assertEquals(0, result.size());
+    }
+
     @Test
     void testParallelEdgesAreNotBridges() {
         int[][] edges = {{0, 1}, {0, 1}};
@@ -66,27 +73,121 @@ void testSelfLoopIsNotBridge() {
         assertEquals(0, result.size());
     }
 
+    @Test
+    void testSingleEdgeIsBridge() {
+        int[][] edges = {{0, 1}};
+
+        List<int[]> result = Bridges.findBridges(2, edges);
+
+        assertEquals(1, result.size());
+        assertArrayEquals(new int[] {0, 1}, result.get(0));
+    }
+
+    @Test
+    void testCycleWithTail() {
+        int[][] edges = {{0, 1}, {1, 2}, {2, 0}, {2, 3}};
+
+        List<int[]> result = Bridges.findBridges(4, edges);
+
+        assertEquals(1, result.size());
+        assertArrayEquals(new int[] {2, 3}, result.get(0));
+    }
+
     @Test
     void testNegativeVertexCountThrowsException() {
-        assertThrows(IllegalArgumentException.class, () -> Bridges.findBridges(-1, new int[0][]));
+        assertThrows(
+            IllegalArgumentException.class,
+            () -> Bridges.findBridges(-1, new int[0][])
+        );
     }
 
     @Test
     void testNullEdgesThrowsException() {
-        assertThrows(IllegalArgumentException.class, () -> Bridges.findBridges(2, null));
+        assertThrows(
+            IllegalArgumentException.class,
+            () -> Bridges.findBridges(2, null)
+        );
     }
 
     @Test
     void testMalformedEdgeThrowsException() {
         int[][] edges = {{0}};
 
-        assertThrows(IllegalArgumentException.class, () -> Bridges.findBridges(2, edges));
+        assertThrows(
+            IllegalArgumentException.class,
+            () -> Bridges.findBridges(2, edges)
+        );
+    }
+
+    @Test
+    void testEdgeWithTooManyVerticesThrowsException() {
+        int[][] edges = {{0, 1, 2}};
+
+        assertThrows(
+            IllegalArgumentException.class,
+            () -> Bridges.findBridges(3, edges)
+        );
+    }
+
+    @Test
+    void testNullEdgeThrowsException() {
+        int[][] edges = {null};
+
+        assertThrows(
+            IllegalArgumentException.class,
+            () -> Bridges.findBridges(2, edges)
+        );
+    }
+
+    @Test
+    void testNegativeFirstVertexThrowsException() {
+        int[][] edges = {{-1, 1}};
+
+        assertThrows(
+            IllegalArgumentException.class,
+            () -> Bridges.findBridges(2, edges)
+        );
+    }
+
+    @Test
+    void testNegativeSecondVertexThrowsException() {
+        int[][] edges = {{0, -1}};
+
+        assertThrows(
+            IllegalArgumentException.class,
+            () -> Bridges.findBridges(2, edges)
+        );
     }
 
     @Test
-    void testInvalidVertexThrowsException() {
+    void testFirstVertexOutOfRangeThrowsException() {
+        int[][] edges = {{2, 1}};
+
+        assertThrows(
+            IllegalArgumentException.class,
+            () -> Bridges.findBridges(2, edges)
+        );
+    }
+
+    @Test
+    void testSecondVertexOutOfRangeThrowsException() {
         int[][] edges = {{0, 2}};
 
-        assertThrows(IllegalArgumentException.class, () -> Bridges.findBridges(2, edges));
+        assertThrows(
+            IllegalArgumentException.class,
+            () -> Bridges.findBridges(2, edges)
+        );
+    }
+
+    @Test
+    void testBridgesAreSortedByBothEndpoints() {
+        int[][] edges = {{2, 3}, {0, 2}, {0, 1}};
+
+        List<int[]> result = Bridges.findBridges(4, edges);
+
+        assertEquals(3, result.size());
+        assertArrayEquals(new int[] {0, 1}, result.get(0));
+        assertArrayEquals(new int[] {0, 2}, result.get(1));
+        assertArrayEquals(new int[] {2, 3}, result.get(2));
     }
 }