Add tests for CountFriendsPairing (#5643)

DIRECTORY.md

@@ -785,6 +785,7 @@
             * [BoardPathTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/BoardPathTest.java)
             * [CatalanNumberTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/CatalanNumberTest.java)
             * [ClimbStairsTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/ClimbStairsTest.java)
+            * [CountFriendsPairingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/CountFriendsPairingTest.java)
             * [EditDistanceTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/EditDistanceTest.java)
             * [EggDroppingTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/EggDroppingTest.java)
             * [KnapsackMemoizationTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/dynamicprogramming/KnapsackMemoizationTest.java)

src/test/java/com/thealgorithms/dynamicprogramming/CountFriendsPairingTest.java

@@ -0,0 +1,50 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public class CountFriendsPairingTest {
+
+    @Test
+    void testSmallCase() {
+        int n = 5;
+        int[] expectedGolombSequence = {1, 2, 2, 3, 3};
+
+        assertTrue(CountFriendsPairing.countFriendsPairing(n, expectedGolombSequence));
+    }
+
+    @Test
+    void testMismatchSequence() {
+        int n = 5;
+        int[] wrongSequence = {1, 2, 2, 2, 3}; // An incorrect sequence
+
+        assertFalse(CountFriendsPairing.countFriendsPairing(n, wrongSequence));
+    }
+
+    @Test
+    void testLargerCase() {
+        int n = 10;
+        int[] expectedGolombSequence = {1, 2, 2, 3, 3, 4, 4, 4, 5, 5};
+
+        assertTrue(CountFriendsPairing.countFriendsPairing(n, expectedGolombSequence));
+    }
+
+    @Test
+    void testEdgeCaseSingleElement() {
+        int n = 1;
+        int[] expectedGolombSequence = {1};
+
+        assertTrue(CountFriendsPairing.countFriendsPairing(n, expectedGolombSequence));
+    }
+
+    @Test
+    void testEmptySequence() {
+        int n = 0;
+        int[] emptySequence = {};
+
+        // Test the case where n is 0 (should handle this gracefully)
+        assertTrue(CountFriendsPairing.countFriendsPairing(n, emptySequence));
+    }
+}