Add tests, remove main & print methods in CoinChange.java (#5642)

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

@@ -0,0 +1,80 @@
+package com.thealgorithms.dynamicprogramming;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class CoinChangeTest {
+
+    @Test
+    void testChangeBasic() {
+        int amount = 12;
+        int[] coins = {2, 4, 5};
+
+        assertEquals(5, CoinChange.change(coins, amount));
+    }
+
+    @Test
+    void testChangeNoCoins() {
+        int amount = 12;
+        int[] coins = {};
+
+        assertEquals(0, CoinChange.change(coins, amount));
+    }
+
+    @Test
+    void testChangeNoAmount() {
+        int amount = 0;
+        int[] coins = {2, 4, 5};
+
+        assertEquals(1, CoinChange.change(coins, amount));
+    }
+
+    @Test
+    void testChangeImpossibleAmount() {
+        int amount = 3;
+        int[] coins = {2, 4, 5};
+
+        assertEquals(0, CoinChange.change(coins, amount));
+    }
+
+    @Test
+    void testMinimumCoinsBasic() {
+        int amount = 12;
+        int[] coins = {2, 4, 5};
+
+        assertEquals(3, CoinChange.minimumCoins(coins, amount));
+    }
+
+    @Test
+    void testMinimumCoinsNoCoins() {
+        int amount = 12;
+        int[] coins = {};
+
+        assertEquals(Integer.MAX_VALUE, CoinChange.minimumCoins(coins, amount));
+    }
+
+    @Test
+    void testMinimumCoinsNoAmount() {
+        int amount = 0;
+        int[] coins = {2, 4, 5};
+
+        assertEquals(0, CoinChange.minimumCoins(coins, amount));
+    }
+
+    @Test
+    void testMinimumCoinsImpossibleAmount() {
+        int amount = 3;
+        int[] coins = {2, 4, 5};
+
+        assertEquals(Integer.MAX_VALUE, CoinChange.minimumCoins(coins, amount));
+    }
+
+    @Test
+    void testMinimumCoinsExactAmount() {
+        int amount = 10;
+        int[] coins = {1, 5, 10};
+
+        assertEquals(1, CoinChange.minimumCoins(coins, amount));
+    }
+}