Add unit tests.

LeetCode/src/LeetCode.Challenges/CoinChange/SolutionV2.cs

@@ -3,9 +3,9 @@
 // This is an optimized solution based on a bottom-up dynamic programming approach instead of recursion.
 // This approach iterates through each possible amount from 1 to the target amount,
 // calculating the minimum number of coins needed to make up each amount.
-public class SolutionV2
+public static class SolutionV2
 {
-    public int CoinChange(int[] coins, int amount)
+    public static int CoinChange(int[] coins, int amount)
     {
         // Initialize an array to store the minimum number of coins needed for each amount.
         var amountMins = new int[amount + 1];

LeetCode/tests/LeetCode.Challenges.UnitTests/CoinChange/SolutionV2Tests.cs

@@ -0,0 +1,37 @@
+using LeetCode.Challenges.CoinChange;
+using Xunit;
+using Shouldly;
+
+namespace LeetCode.Challenges.UnitTests.CoinChange;
+
+public class SolutionV2Tests
+{
+    [Theory]
+    [MemberData(nameof(CoinChangeTestCases))]
+    public void CoinChange_ShouldReturnExpectedResult(int[] coins, int amount, int expected)
+    {
+        SolutionV2.CoinChange(coins, amount).ShouldBe(expected);
+    }
+
+    public static IEnumerable<object[]> CoinChangeTestCases()
+    {
+        yield return [new[] { 1, 2, 5 }, 11, 3];
+        yield return [new[] { 2 }, 3, -1];
+        yield return [new[] { 1 }, 0, 0];
+        yield return [new[] { 186, 419, 83, 408 }, 6249, 20];
+        yield return [new[] { 1, 3, 4 }, 6, 2];
+        yield return [new[] { 5 }, 5, 1];
+        yield return [new[] { 5 }, 0, 0];
+        yield return [new[] { 5 }, 2, -1];
+        yield return [new[] { 2, 5, 10 }, 1, -1];
+        yield return [new[] { 10, 5 }, 20, 2];
+        yield return [new[] { 1, 5, 10, 25 }, 30, 2];
+        yield return [new[] { 2, 3 }, 7, 3];
+        yield return [new[] { 1, 2, 5 }, 100, 20];
+        yield return [new[] { 7, 3, 2 }, 8, 3];
+        yield return [new[] { 1, 7, 10 }, 14, 2];
+        yield return [new[] { 1, 3, 4, 7 }, 15, 3];
+        yield return [new[] { 25, 50, 100 }, 30, -1];
+        yield return [new[] { 9, 6, 5, 1 }, 11, 2];
+    }
+}