factorail test

Author: Ayush41

src/test/java/com/thealgorithms/recursion/FactorialTest.java

@@ -0,0 +1,36 @@
+package com.thealgorithms.recursion;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class FactorialTest {
+
+    @Test
+    public void testFactorialOfZero() {
+        assertEquals(1, Factorial.factorial(0));
+    }
+
+    @Test
+    public void testFactorialOfOne() {
+        assertEquals(1, Factorial.factorial(1));
+    }
+
+    @Test
+    public void testFactorialOfPositiveNumbers() {
+        assertEquals(120, Factorial.factorial(5));
+        assertEquals(720, Factorial.factorial(6));
+        assertEquals(5040, Factorial.factorial(7));
+    }
+
+    @Test
+    public void testFactorialOfTen() {
+        assertEquals(3628800, Factorial.factorial(10));
+    }
+
+    @Test
+    public void testNegativeNumberThrowsException() {
+        assertThrows(IllegalArgumentException.class, () -> Factorial.factorial(-1));
+    }
+}