#4369 Enhance UniquePaths (#4373)

* Enhance UnquiePaths DP problem solution

* Update testcases

* Linter issue resolved

* Code review comments

* Code review comments

* Code review comments

* Code review comments

---------

Co-authored-by: Piotr Idzik <65706193+vil02@users.noreply.github.com>

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

@@ -0,0 +1,58 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+public class UniquePathsTests {
+
+    @Test
+    public void testUniquePaths_3x3() {
+        assertEquals(6, UniquePaths.uniquePaths(3, 3));
+    }
+
+    @Test
+    public void testUniquePaths_1x1() {
+        assertEquals(1, UniquePaths.uniquePaths(1, 1));
+    }
+
+    @Test
+    public void testUniquePaths_3x7() {
+        assertEquals(28, UniquePaths.uniquePaths(3, 7));
+    }
+
+    @Test
+    public void testUniquePaths_7x3() {
+        assertEquals(28, UniquePaths.uniquePaths(7, 3));
+    }
+
+    @Test
+    public void testUniquePaths_100x100() {
+        assertThrows(ArithmeticException.class, () -> UniquePaths.uniquePaths(100, 100));
+    }
+
+    @Test
+    public void testUniquePaths2_3x3() {
+        assertEquals(6, UniquePaths.uniquePaths2(3, 3));
+    }
+
+    @Test
+    public void testUniquePaths2_1x1() {
+        assertEquals(1, UniquePaths.uniquePaths2(1, 1));
+    }
+
+    @Test
+    public void testUniquePaths2_3x7() {
+        assertEquals(28, UniquePaths.uniquePaths2(3, 7));
+    }
+
+    @Test
+    public void testUniquePaths2_7x3() {
+        assertEquals(28, UniquePaths.uniquePaths2(7, 3));
+    }
+
+    @Test
+    public void testUniquePaths2_100x100() {
+        assertThrows(ArithmeticException.class, () -> UniquePaths.uniquePaths2(100, 100));
+    }
+}