Add tests, add IllegalArgumentException, remove main in `WineProb… (#5662)

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

@@ -0,0 +1,72 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the WineProblem class.
+ * This test class verifies the correctness of the wine selling problem solutions.
+ */
+class WineProblemTest {
+
+    /**
+     * Test for wpRecursion method.
+     */
+    @Test
+    void testWpRecursion() {
+        int[] wines = {2, 3, 5, 1, 4}; // Prices of wines
+        int expectedProfit = 50; // The expected maximum profit
+        assertEquals(expectedProfit, WineProblem.wpRecursion(wines, 0, wines.length - 1), "The maximum profit using recursion should be 50.");
+    }
+
+    /**
+     * Test for wptd method (Top-Down DP with Memoization).
+     */
+    @Test
+    void testWptd() {
+        int[] wines = {2, 3, 5, 1, 4}; // Prices of wines
+        int expectedProfit = 50; // The expected maximum profit
+        assertEquals(expectedProfit, WineProblem.wptd(wines, 0, wines.length - 1, new int[wines.length][wines.length]), "The maximum profit using top-down DP should be 50.");
+    }
+
+    /**
+     * Test for wpbu method (Bottom-Up DP with Tabulation).
+     */
+    @Test
+    void testWpbu() {
+        int[] wines = {2, 3, 5, 1, 4}; // Prices of wines
+        int expectedProfit = 50; // The expected maximum profit
+        assertEquals(expectedProfit, WineProblem.wpbu(wines), "The maximum profit using bottom-up DP should be 50.");
+    }
+
+    /**
+     * Test with a single wine.
+     */
+    @Test
+    void testSingleWine() {
+        int[] wines = {10}; // Only one wine
+        int expectedProfit = 10; // Selling the only wine at year 1
+        assertEquals(expectedProfit, WineProblem.wpbu(wines), "The maximum profit for a single wine should be 10.");
+    }
+
+    /**
+     * Test with multiple wines of the same price.
+     */
+    @Test
+    void testSamePriceWines() {
+        int[] wines = {5, 5, 5}; // All wines have the same price
+        int expectedProfit = 30; // Profit is 5 * (1 + 2 + 3)
+        assertEquals(expectedProfit, WineProblem.wpbu(wines), "The maximum profit with same price wines should be 30.");
+    }
+
+    /**
+     * Test with no wines.
+     */
+    @Test
+    void testNoWines() {
+        int[] wines = {};
+        assertThrows(IllegalArgumentException.class, () -> WineProblem.wpbu(wines), "The maximum profit for no wines should throw an IllegalArgumentException.");
+    }
+}