Lab 2: unit tests, Mockito, refactored PaymentProcessor and TDD Shopp…

pom.xml

@@ -9,45 +9,65 @@
     <version>1.0-SNAPSHOT</version>
 
     <properties>
-        <maven.compiler.release>23</maven.compiler.release>
+        <maven.compiler.release>25</maven.compiler.release>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+
+        <junit.version>5.11.4</junit.version>
+        <assertj.version>3.27.3</assertj.version>
+        <mockito.version>5.15.2</mockito.version>
+        <maven.compiler.plugin.version>3.13.0</maven.compiler.plugin.version>
+        <surefire.version>3.5.2</surefire.version>
+        <failsafe.version>3.5.2</failsafe.version>
+        <jacoco.version>0.8.13</jacoco.version>
     </properties>
+
     <dependencies>
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter</artifactId>
-            <version>5.11.4</version>
+            <version>${junit.version}</version>
             <scope>test</scope>
         </dependency>
+
         <dependency>
             <groupId>org.assertj</groupId>
             <artifactId>assertj-core</artifactId>
-            <version>3.27.3</version>
+            <version>${assertj.version}</version>
             <scope>test</scope>
         </dependency>
+
         <dependency>
             <groupId>org.mockito</groupId>
             <artifactId>mockito-junit-jupiter</artifactId>
-            <version>5.15.2</version>
+            <version>${mockito.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <version>${mockito.version}</version>
             <scope>test</scope>
         </dependency>
     </dependencies>
+
     <build>
         <plugins>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
-                <version>3.13.0</version>
+                <version>${maven.compiler.plugin.version}</version>
             </plugin>
+
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-surefire-plugin</artifactId>
-                <version>3.5.2</version>
+                <version>${surefire.version}</version>
             </plugin>
+
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-failsafe-plugin</artifactId>
-                <version>3.5.2</version>
+                <version>${failsafe.version}</version>
                 <executions>
                     <execution>
                         <goals>
@@ -57,23 +77,24 @@
                     </execution>
                 </executions>
             </plugin>
+
             <plugin>
                 <groupId>org.jacoco</groupId>
                 <artifactId>jacoco-maven-plugin</artifactId>
-                <version>0.8.12</version>
+                <version>${jacoco.version}</version>
                 <configuration>
-                    <skip>true</skip>
+                    <skip>false</skip>
                 </configuration>
                 <executions>
                     <execution>
-                        <id>default-prepare-agent</id>
+                        <id>prepare-agent</id>
                         <goals>
                             <goal>prepare-agent</goal>
                         </goals>
                     </execution>
                     <execution>
-                        <id>default-report</id>
-                        <phase>prepare-package</phase>
+                        <id>report</id>
+                        <phase>verify</phase>
                         <goals>
                             <goal>report</goal>
                         </goals>

src/main/java/com/example/payment/PaymentChargeResponse.java

@@ -0,0 +1,5 @@
+package com.example.payment;
+
+public interface PaymentChargeResponse {
+    boolean isSuccess();
+}

src/main/java/com/example/payment/PaymentEmailSender.java

@@ -0,0 +1,5 @@
+package com.example.payment;
+
+public interface PaymentEmailSender {
+    void sendPaymentConfirmation(String toEmail, double amount);
+}

src/main/java/com/example/payment/PaymentGateway.java

@@ -0,0 +1,5 @@
+package com.example.payment;
+
+public interface PaymentGateway {
+    PaymentChargeResponse charge(String apiKey, double amount);
+}

src/main/java/com/example/payment/PaymentProcessor.java

@@ -1,23 +1,39 @@
 package com.example.payment;
 
-//public class PaymentProcessor {
-//    private static final String API_KEY = "sk_test_123456";
-//
-//    public boolean processPayment(double amount) {
-//        // Anropar extern betaltjänst direkt med statisk API-nyckel
-//        PaymentApiResponse response = PaymentApi.charge(API_KEY, amount);
-//
-//        // Skriver till databas direkt
-//        if (response.isSuccess()) {
-//            DatabaseConnection.getInstance()
-//                    .executeUpdate("INSERT INTO payments (amount, status) VALUES (" + amount + ", 'SUCCESS')");
-//        }
-//
-//        // Skickar e-post direkt
-//        if (response.isSuccess()) {
-//            EmailService.sendPaymentConfirmation("user@example.com", amount);
-//        }
-//
-//        return response.isSuccess();
-//    }
-//}
+import java.util.Objects;
+
+public class PaymentProcessor {
+    private final PaymentGateway paymentGateway;
+    private final PaymentRepository paymentRepository;
+    private final PaymentEmailSender emailSender;
+    private final String apiKey;
+    private final String confirmationEmailTo;
+
+    public PaymentProcessor(PaymentGateway paymentGateway,
+                            PaymentRepository paymentRepository,
+                            PaymentEmailSender emailSender,
+                            String apiKey,
+                            String confirmationEmailTo) {
+        this.paymentGateway = Objects.requireNonNull(paymentGateway, "paymentGateway");
+        this.paymentRepository = Objects.requireNonNull(paymentRepository, "paymentRepository");
+        this.emailSender = Objects.requireNonNull(emailSender, "emailSender");
+        this.apiKey = Objects.requireNonNull(apiKey, "apiKey");
+        this.confirmationEmailTo = Objects.requireNonNull(confirmationEmailTo, "confirmationEmailTo");
+    }
+
+    public boolean processPayment(double amount) {
+        if (amount <= 0.0) {
+            throw new IllegalArgumentException("amount måste vara > 0");
+        }
+
+        PaymentChargeResponse response = paymentGateway.charge(apiKey, amount);
+
+        if (response.isSuccess()) {
+            paymentRepository.saveSuccessfulPayment(amount);
+            emailSender.sendPaymentConfirmation(confirmationEmailTo, amount);
+            return true;
+        }
+
+        return false;
+    }
+}

src/main/java/com/example/payment/PaymentRepository.java

@@ -0,0 +1,5 @@
+package com.example.payment;
+
+public interface PaymentRepository {
+    void saveSuccessfulPayment(double amount);
+}

src/main/java/shop/Discount.java

@@ -0,0 +1,7 @@
+package shop;
+
+import java.math.BigDecimal;
+
+public interface Discount {
+    BigDecimal apply(BigDecimal currentTotal);
+}

src/main/java/shop/FixedAmountDiscount.java

@@ -0,0 +1,19 @@
+package shop;
+
+import java.math.BigDecimal;
+import java.util.Objects;
+
+public final class FixedAmountDiscount implements Discount {
+    private final BigDecimal amount;
+
+    public FixedAmountDiscount(BigDecimal amount) {
+        this.amount = Objects.requireNonNull(amount, "amount");
+        if (amount.signum() < 0) throw new IllegalArgumentException("amount måste vara >= 0");
+    }
+
+    @Override
+    public BigDecimal apply(BigDecimal currentTotal) {
+        Objects.requireNonNull(currentTotal, "currentTotal");
+        return currentTotal.subtract(amount);
+    }
+}

src/main/java/shop/PercentageDiscount.java

@@ -0,0 +1,21 @@
+package shop;
+
+import java.math.BigDecimal;
+import java.math.RoundingMode;
+import java.util.Objects;
+
+public final class PercentageDiscount implements Discount {
+    private final BigDecimal percent;
+
+    public PercentageDiscount(BigDecimal percent) {
+        this.percent = Objects.requireNonNull(percent, "percent");
+        if (percent.signum() < 0) throw new IllegalArgumentException("percent måste vara >= 0");
+    }
+
+    @Override
+    public BigDecimal apply(BigDecimal currentTotal) {
+        Objects.requireNonNull(currentTotal, "currentTotal");
+        BigDecimal factor = BigDecimal.ONE.subtract(percent.divide(new BigDecimal("100"), 10, RoundingMode.HALF_UP));
+        return currentTotal.multiply(factor);
+    }
+}

src/main/java/shop/Product.java

@@ -0,0 +1,31 @@
+package shop;
+
+import java.math.BigDecimal;
+import java.util.Objects;
+
+public final class Product {
+    private final String id;
+    private final String name;
+    private final BigDecimal unitPrice;
+
+    public Product(String id, String name, BigDecimal unitPrice) {
+        if (id == null || id.isBlank()) throw new IllegalArgumentException("id");
+        if (name == null || name.isBlank()) throw new IllegalArgumentException("name");
+        this.id = id;
+        this.name = name;
+        this.unitPrice = Objects.requireNonNull(unitPrice, "unitPrice");
+        if (unitPrice.signum() < 0) throw new IllegalArgumentException("unitPrice måste vara >= 0");
+    }
+
+    public String id() {
+        return id;
+    }
+
+    public String name() {
+        return name;
+    }
+
+    public BigDecimal unitPrice() {
+        return unitPrice;
+    }
+}

src/main/java/shop/ShoppingCart.java

@@ -0,0 +1,82 @@
+package shop;
+
+import java.math.BigDecimal;
+import java.math.RoundingMode;
+import java.util.*;
+
+public final class ShoppingCart {
+
+    private final Map<String, CartLine> lines = new HashMap<>();
+    private final List<Discount> discounts = new ArrayList<>();
+
+    public void addItem(Product product, int quantity) {
+        if (product == null) throw new IllegalArgumentException("product");
+        if (quantity <= 0) throw new IllegalArgumentException("quantity måste vara > 0");
+
+        lines.merge(
+                product.id(),
+                new CartLine(product, quantity),
+                (existing, added) -> new CartLine(existing.product(), existing.quantity() + added.quantity())
+        );
+    }
+
+    public boolean removeItem(String productId) {
+        if (productId == null) throw new IllegalArgumentException("productId");
+        return lines.remove(productId) != null;
+    }
+
+    public void updateQuantity(String productId, int newQuantity) {
+        if (productId == null) throw new IllegalArgumentException("productId");
+        if (newQuantity < 0) throw new IllegalArgumentException("newQuantity måste vara >= 0");
+
+        CartLine existing = lines.get(productId);
+        if (existing == null) {
+            throw new IllegalArgumentException("Produkt finns inte i kundvagnen: " + productId);
+        }
+
+        if (newQuantity == 0) {
+            lines.remove(productId);
+            return;
+        }
+
+        lines.put(productId, new CartLine(existing.product(), newQuantity));
+    }
+
+    public int getQuantity(String productId) {
+        CartLine line = lines.get(productId);
+        return line == null ? 0 : line.quantity();
+    }
+
+    public BigDecimal totalBeforeDiscount() {
+        BigDecimal total = BigDecimal.ZERO;
+        for (CartLine line : lines.values()) {
+            total = total.add(line.product().unitPrice().multiply(BigDecimal.valueOf(line.quantity())));
+        }
+        return money(total);
+    }
+
+    public void applyDiscount(Discount discount) {
+        if (discount == null) throw new IllegalArgumentException("discount");
+        discounts.add(discount);
+    }
+
+    public BigDecimal total() {
+        BigDecimal total = totalBeforeDiscount();
+        for (Discount discount : discounts) {
+            total = discount.apply(total);
+        }
+        if (total.signum() < 0) total = BigDecimal.ZERO;
+        return money(total);
+    }
+
+    private static BigDecimal money(BigDecimal value) {
+        return value.setScale(2, RoundingMode.HALF_UP);
+    }
+
+    private record CartLine(Product product, int quantity) {
+        private CartLine {
+            Objects.requireNonNull(product, "product");
+            if (quantity <= 0) throw new IllegalArgumentException("quantity måste vara > 0");
+        }
+    }
+}