Add climbing stairs (#4168)

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

@@ -0,0 +1,24 @@
+package com.thealgorithms.dynamicprogramming;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+
+public class climbStairsTest {
+
+    @Test
+    void climbStairsTestForTwo(){assertEquals(2, ClimbingStairs.numberOfWays(2));}
+
+    @Test
+    void climbStairsTestForZero(){assertEquals(0, ClimbingStairs.numberOfWays(0));}
+
+    @Test
+    void climbStairsTestForOne(){assertEquals(1, ClimbingStairs.numberOfWays(1));}
+
+    @Test
+    void climbStairsTestForFive(){assertEquals(8, ClimbingStairs.numberOfWays(5));}
+
+    @Test
+    void climbStairsTestForThree(){assertEquals(3, ClimbingStairs.numberOfWays(3));}
+}