Add unit tests for Coffee Vending Machine

solutions/java/pom.xml

@@ -0,0 +1,35 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>coffeevendingmachine</groupId>
+    <artifactId>coffeevendingmachine</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <packaging>jar</packaging>
+    <name>Coffee Vending Machine</name>
+    <properties>
+        <maven.compiler.source>1.8</maven.compiler.source>
+        <maven.compiler.target>1.8</maven.compiler.target>
+        <junit.jupiter.version>5.10.2</junit.jupiter.version>
+    </properties>
+    <dependencies>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>${junit.jupiter.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>3.2.5</version>
+                <configuration>
+                    <useModulePath>false</useModulePath>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+</project>

solutions/java/src/coffeevendingmachine/CoffeeVendingMachine.java

@@ -73,4 +73,8 @@ public void showIngredients() {
         System.out.println("Ingredient Levels:");
         ingredientStore.getAllIngredients().forEach((k, v) -> System.out.println(k + ": " + v));
     }
+
+    public Map<String, Integer> showIngredientsMap() {
+        return ingredientStore.getAllIngredients();
+    }
 }

solutions/java/test/coffeevendingmachine/CoffeeVendingMachineTest.java

@@ -0,0 +1,116 @@
+package coffeevendingmachine;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.DisplayName;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+import java.util.Map;
+
+public class CoffeeVendingMachineTest {
+
+    private CoffeeVendingMachine machine;
+    private final ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+    private final PrintStream originalOut = System.out;
+
+    @BeforeEach
+    void setUp() {
+        machine = CoffeeVendingMachine.getInstance();
+        System.setOut(new PrintStream(outputStream));
+
+        // Reset and refill ingredients for each test
+        machine.refillIngredient("Water", 150);
+        machine.refillIngredient("Coffee", 100);
+        machine.refillIngredient("Milk", 100);
+    }
+
+    @Test
+    @DisplayName("Test coffee selection")
+    void testSelectCoffee() {
+        CoffeeRecipe espresso = machine.selectCoffee("Espresso");
+        assertEquals("Espresso", espresso.getName());
+        assertEquals(2.5, espresso.getPrice());
+        assertEquals(50, espresso.getRecipe().get("Water"));
+        assertEquals(20, espresso.getRecipe().get("Coffee"));
+    }
+
+    @Test
+    @DisplayName("Test invalid coffee selection")
+    void testInvalidCoffeeSelection() {
+        Exception exception = assertThrows(RuntimeException.class, () -> {
+            machine.selectCoffee("MochaCoffee");
+        });
+
+        String expectedMessage = "Invalid coffee recipe: MochaCoffee";
+        String actualMessage = exception.getMessage();
+
+        assertTrue(actualMessage.contains(expectedMessage));
+    }
+
+    @Test
+    @DisplayName("Test successful coffee dispensing")
+    void testDispenseCoffee() {
+        CoffeeRecipe latte = machine.selectCoffee("Latte");
+        machine.dispenseCoffee(latte, new Payment(4.0));
+
+        String output = outputStream.toString();
+        assertTrue(output.contains("Dispensing: Latte"));
+        assertTrue(output.contains("Processing Payment"));
+        assertTrue(output.contains("Please collect your change: $1.0"));
+    }
+
+    @Test
+    @DisplayName("Test insufficient payment")
+    void testInsufficientPayment() {
+        CoffeeRecipe cappuccino = machine.selectCoffee("Cappuccino");
+
+        Exception exception = assertThrows(RuntimeException.class, () -> {
+            machine.dispenseCoffee(cappuccino, new Payment(2.0));
+        });
+
+        String expectedMessage = "Insufficient payment for Cappuccino";
+        String actualMessage = exception.getMessage();
+
+        assertTrue(actualMessage.contains(expectedMessage));
+    }
+
+
+
+    @Test
+    @DisplayName("Test ingredient consumption")
+    void testIngredientConsumption() {
+        CoffeeRecipe latte = machine.selectCoffee("Latte");
+
+        // Check initial levels
+        Map<String, Integer> beforeLevels = machine.showIngredientsMap();
+        int initialWaterLevel = beforeLevels.get("Water");
+        int initialCoffeeLevel = beforeLevels.get("Coffee");
+        int initialMilkLevel = beforeLevels.get("Milk");
+
+        machine.dispenseCoffee(latte, new Payment(3.0));
+
+        // Check levels after dispensing
+        Map<String, Integer> afterLevels = machine.showIngredientsMap();
+        assertEquals(initialWaterLevel - 50, afterLevels.get("Water").intValue());
+        assertEquals(initialCoffeeLevel - 20, afterLevels.get("Coffee").intValue());
+        assertEquals(initialMilkLevel - 30, afterLevels.get("Milk").intValue());
+    }
+
+    @Test
+    @DisplayName("Test ingredient refill")
+    void testIngredientRefill() {
+        // First check initial level
+        Map<String, Integer> beforeLevels = machine.showIngredientsMap();
+        int initialWaterLevel = beforeLevels.get("Water");
+
+        // Add more water
+        machine.refillIngredient("Water", 50);
+
+        // Check after refill
+        Map<String, Integer> afterLevels = machine.showIngredientsMap();
+        assertEquals(initialWaterLevel + 50, afterLevels.get("Water").intValue());
+    }
+}