Add tests, remove main method, improve docs in BruteForceKnapsack (#5641)

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

@@ -0,0 +1,96 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class BruteForceKnapsackTest {
+
+    @Test
+    void testKnapSackBasicCase() {
+        int[] val = {60, 100, 120};
+        int[] wt = {10, 20, 30};
+        int w = 50;
+        int n = val.length;
+
+        // The expected result for this case is 220 (items 2 and 3 are included)
+        assertEquals(220, BruteForceKnapsack.knapSack(w, wt, val, n));
+    }
+
+    @Test
+    void testKnapSackNoItems() {
+        int[] val = {};
+        int[] wt = {};
+        int w = 50;
+        int n = val.length;
+
+        // With no items, the maximum value should be 0
+        assertEquals(0, BruteForceKnapsack.knapSack(w, wt, val, n));
+    }
+
+    @Test
+    void testKnapSackZeroCapacity() {
+        int[] val = {60, 100, 120};
+        int[] wt = {10, 20, 30};
+        int w = 0;
+        int n = val.length;
+
+        // With a knapsack of 0 capacity, no items can be included, so the value is 0
+        assertEquals(0, BruteForceKnapsack.knapSack(w, wt, val, n));
+    }
+
+    @Test
+    void testKnapSackSingleItemFits() {
+        int[] val = {100};
+        int[] wt = {20};
+        int w = 30;
+        int n = val.length;
+
+        // Only one item, and it fits in the knapsack, so the result is 100
+        assertEquals(100, BruteForceKnapsack.knapSack(w, wt, val, n));
+    }
+
+    @Test
+    void testKnapSackSingleItemDoesNotFit() {
+        int[] val = {100};
+        int[] wt = {20};
+        int w = 10;
+        int n = val.length;
+
+        // Single item does not fit in the knapsack, so the result is 0
+        assertEquals(0, BruteForceKnapsack.knapSack(w, wt, val, n));
+    }
+
+    @Test
+    void testKnapSackAllItemsFit() {
+        int[] val = {20, 30, 40};
+        int[] wt = {1, 2, 3};
+        int w = 6;
+        int n = val.length;
+
+        // All items fit into the knapsack, so the result is the sum of all values (20 + 30 + 40 = 90)
+        assertEquals(90, BruteForceKnapsack.knapSack(w, wt, val, n));
+    }
+
+    @Test
+    void testKnapSackNoneFit() {
+        int[] val = {100, 200, 300};
+        int[] wt = {100, 200, 300};
+        int w = 50;
+        int n = val.length;
+
+        // None of the items fit into the knapsack, so the result is 0
+        assertEquals(0, BruteForceKnapsack.knapSack(w, wt, val, n));
+    }
+
+    @Test
+    void testKnapSackSomeItemsFit() {
+        int[] val = {60, 100, 120};
+        int[] wt = {10, 20, 30};
+        int w = 40;
+        int n = val.length;
+
+        // Here, only the 2nd and 1st items should be included for a total value of 160
+        assertEquals(180, BruteForceKnapsack.knapSack(w, wt, val, n));
+    }
+}