《軟件工程》第 12 章

? ?軟件測試是確保軟件質量的關鍵環節，它通過執行程序來發現錯誤，驗證軟件是否滿足需求。本章將依據目錄，結合 Java 代碼示例、可視化圖表，深入講解軟件測試的概念、過程、方法及實踐。

12.1 軟件測試的概念

12.1.1 軟件測試的任務

軟件測試的主要任務是：

發現錯誤：通過執行程序，找出代碼中的缺陷和邏輯錯誤。
驗證功能：確保軟件滿足用戶需求和規格說明。
評估質量：對軟件的可靠性、性能等質量屬性進行評估。

12.1.2 測試階段的信息流程

測試階段的信息流程：

展示測試過程中的信息流轉。

12.1.3 測試用例及其設計

? ?測試用例是為測試而設計的一組輸入和預期輸出，用于驗證軟件的特定功能。例如，測試一個簡單的加法函數的測試用例：

public class Calculator {public int add(int a, int b) {return a + b;}
}// 對應的測試用例（使用JUnit框架）
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;public class CalculatorTest {@Testpublic void testAddPositiveNumbers() {Calculator calculator = new Calculator();int result = calculator.add(3, 5);assertEquals(8, result); // 預期結果為8}@Testpublic void testAddNegativeNumbers() {Calculator calculator = new Calculator();int result = calculator.add(-3, -5);assertEquals(-8, result); // 預期結果為-8}
}

12.1.4 軟件測試的原則

軟件測試應遵循以下原則：

盡早測試：測試應從軟件開發的早期階段開始，如需求分析和設計階段。
全面測試：覆蓋所有可能的輸入和場景，包括邊界條件和異常情況。
避免自測：開發人員應避免測試自己編寫的代碼，減少主觀因素影響。
記錄測試結果：詳細記錄測試過程和結果，便于追蹤和分析。

12.2 軟件測試的過程模型

? ?軟件測試的過程模型通常與軟件開發過程模型對應，常見的有 V 模型、W 模型等。以 V 模型為例：

展示 V 模型中測試階段與開發階段的對應關系。

12.3 軟件測試方法

12.3.1 白盒測試

白盒測試基于代碼的內部結構和邏輯，主要技術包括：

語句覆蓋：確保每個語句至少執行一次。
判定覆蓋：確保每個判定的真假分支至少執行一次。
條件覆蓋：確保每個判定中的每個條件的可能取值至少執行一次。

示例代碼及測試用例：

public class ControlFlow {public boolean checkNumber(int num) {if (num > 10 && num % 2 == 0) {return true;} else {return false;}}
}// 白盒測試用例
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;public class ControlFlowTest {@Testpublic void testCheckNumberTrue() {ControlFlow cf = new ControlFlow();assertTrue(cf.checkNumber(12)); // 覆蓋true分支}@Testpublic void testCheckNumberFalse1() {ControlFlow cf = new ControlFlow();assertFalse(cf.checkNumber(5)); // 覆蓋false分支（num <= 10）}@Testpublic void testCheckNumberFalse2() {ControlFlow cf = new ControlFlow();assertFalse(cf.checkNumber(11)); // 覆蓋false分支（num為奇數）}
}

12.3.2 黑盒測試

? ?黑盒測試基于軟件的外部功能和需求，不考慮內部實現。主要技術包括：

等價類劃分：將輸入域劃分為若干等價類，從每個等價類中選取代表性值作為測試用例。
邊界值分析：選擇輸入域的邊界值作為測試用例，如最小值、最大值、剛好超過邊界的值。
錯誤推測法：基于經驗和直覺推測可能的錯誤，設計針對性的測試用例。

以三角形分類函數為例：

public class TriangleClassifier {public String classify(int a, int b, int c) {// 檢查是否構成三角形if (a <= 0 || b <= 0 || c <= 0 || a + b <= c || a + c <= b || b + c <= a) {return "非三角形";}// 檢查等邊三角形if (a == b && b == c) {return "等邊三角形";}// 檢查等腰三角形if (a == b || a == c || b == c) {return "等腰三角形";}// 普通三角形return "普通三角形";}
}// 黑盒測試用例（等價類劃分和邊界值分析）
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;public class TriangleClassifierTest {@Testpublic void testEquilateralTriangle() {TriangleClassifier tc = new TriangleClassifier();assertEquals("等邊三角形", tc.classify(3, 3, 3));}@Testpublic void testIsoscelesTriangle() {TriangleClassifier tc = new TriangleClassifier();assertEquals("等腰三角形", tc.classify(3, 3, 4));}@Testpublic void testScaleneTriangle() {TriangleClassifier tc = new TriangleClassifier();assertEquals("普通三角形", tc.classify(3, 4, 5));}@Testpublic void testNotTriangle() {TriangleClassifier tc = new TriangleClassifier();assertEquals("非三角形", tc.classify(1, 2, 3));}@Testpublic void testBoundaryValues() {TriangleClassifier tc = new TriangleClassifier();assertEquals("非三角形", tc.classify(0, 3, 4)); // 邊界值0assertEquals("等腰三角形", tc.classify(2, 2, 4)); // 邊界值a+b=c}
}

12.4 軟件測試活動及實施策略

12.4.1 單元測試

? ?單元測試是對軟件中的最小可測試單元（如方法、類）進行測試。例如，測試一個棧類的基本操作：

import java.util.EmptyStackException;public class Stack {private int[] array;private int top;private int capacity;public Stack(int capacity) {this.capacity = capacity;this.array = new int[capacity];this.top = -1;}public void push(int item) {if (top == capacity - 1) {throw new StackOverflowError("棧已滿");}array[++top] = item;}public int pop() {if (isEmpty()) {throw new EmptyStackException();}return array[top--];}public int peek() {if (isEmpty()) {throw new EmptyStackException();}return array[top];}public boolean isEmpty() {return top == -1;}
}// 單元測試用例
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;public class StackTest {private Stack stack;@BeforeEachpublic void setUp() {stack = new Stack(5);}@Testpublic void testPushAndPop() {stack.push(10);stack.push(20);assertEquals(20, stack.pop());assertEquals(10, stack.pop());}@Testpublic void testPeek() {stack.push(10);assertEquals(10, stack.peek());assertEquals(10, stack.peek()); // 多次peek不應改變棧}@Testpublic void testEmptyStack() {assertTrue(stack.isEmpty());assertThrows(EmptyStackException.class, () -> stack.pop());assertThrows(EmptyStackException.class, () -> stack.peek());}@Testpublic void testStackOverflow() {for (int i = 0; i < 5; i++) {stack.push(i);}assertThrows(StackOverflowError.class, () -> stack.push(5));}
}

12.4.2 集成測試

? ?集成測試是將多個單元組合成更大的模塊進行測試，驗證模塊間的交互。例如，測試一個簡單的訂單處理系統：

// 訂單類
public class Order {private String orderId;private double totalAmount;private boolean paid;public Order(String orderId, double totalAmount) {this.orderId = orderId;this.totalAmount = totalAmount;this.paid = false;}public String getOrderId() {return orderId;}public double getTotalAmount() {return totalAmount;}public boolean isPaid() {return paid;}public void setPaid(boolean paid) {this.paid = paid;}
}// 支付服務接口
public interface PaymentService {boolean processPayment(double amount);
}// 訂單處理服務
public class OrderService {private PaymentService paymentService;public OrderService(PaymentService paymentService) {this.paymentService = paymentService;}public boolean checkout(Order order) {if (order.isPaid()) {return false;}boolean paymentResult = paymentService.processPayment(order.getTotalAmount());if (paymentResult) {order.setPaid(true);return true;}return false;}
}// 集成測試用例
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;
import static org.mockito.Mockito.*;public class OrderServiceIntegrationTest {@Testpublic void testCheckoutSuccess() {// 創建模擬的支付服務PaymentService paymentService = mock(PaymentService.class);when(paymentService.processPayment(100.0)).thenReturn(true);// 創建訂單服務并注入模擬的支付服務OrderService orderService = new OrderService(paymentService);Order order = new Order("ORD123", 100.0);// 執行測試boolean result = orderService.checkout(order);// 驗證結果assertTrue(result);assertTrue(order.isPaid());verify(paymentService, times(1)).processPayment(100.0);}@Testpublic void testCheckoutFailure() {PaymentService paymentService = mock(PaymentService.class);when(paymentService.processPayment(100.0)).thenReturn(false);OrderService orderService = new OrderService(paymentService);Order order = new Order("ORD123", 100.0);boolean result = orderService.checkout(order);assertFalse(result);assertFalse(order.isPaid());verify(paymentService, times(1)).processPayment(100.0);}
}

12.4.3 確認測試

? ?確認測試驗證軟件是否滿足用戶需求和規格說明，通常包括功能測試、性能測試等。例如，測試一個用戶注冊功能：

// 用戶類
public class User {private String username;private String email;private String password;public User(String username, String email, String password) {this.username = username;this.email = email;this.password = password;}// Getters and setterspublic String getUsername() { return username; }public String getEmail() { return email; }public String getPassword() { return password; }
}// 用戶服務接口
public interface UserService {boolean registerUser(User user);boolean isValidEmail(String email);
}// 用戶服務實現
public class UserServiceImpl implements UserService {@Overridepublic boolean registerUser(User user) {// 驗證郵箱格式if (!isValidEmail(user.getEmail())) {return false;}// 驗證用戶名和密碼長度if (user.getUsername().length() < 3 || user.getPassword().length() < 6) {return false;}// 模擬保存用戶到數據庫System.out.println("用戶注冊成功: " + user.getUsername());return true;}@Overridepublic boolean isValidEmail(String email) {// 簡單的郵箱格式驗證return email.matches("^[a-zA-Z0-9_+&*-]+(?:\\.[a-zA-Z0-9_+&*-]+)*@(?:[a-zA-Z0-9-]+\\.)+[a-zA-Z]{2,7}$");}
}// 確認測試用例
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;public class UserServiceVerificationTest {@Testpublic void testRegisterUserSuccess() {UserService userService = new UserServiceImpl();User user = new User("john_doe", "john@example.com", "password123");assertTrue(userService.registerUser(user));}@Testpublic void testRegisterUserInvalidEmail() {UserService userService = new UserServiceImpl();User user = new User("john_doe", "invalid_email", "password123");assertFalse(userService.registerUser(user));}@Testpublic void testRegisterUserShortUsername() {UserService userService = new UserServiceImpl();User user = new User("jo", "john@example.com", "password123");assertFalse(userService.registerUser(user));}@Testpublic void testRegisterUserShortPassword() {UserService userService = new UserServiceImpl();User user = new User("john_doe", "john@example.com", "pass");assertFalse(userService.registerUser(user));}
}

12.4.4 系統測試

? ? 系統測試將軟件作為一個整體進行測試，驗證系統是否滿足需求。例如，測試一個在線購物系統的完整流程：

// 商品類
public class Product {private String productId;private String name;private double price;private int stock;public Product(String productId, String name, double price, int stock) {this.productId = productId;this.name = name;this.price = price;this.stock = stock;}// Getters and setterspublic String getProductId() { return productId; }public String getName() { return name; }public double getPrice() { return price; }public int getStock() { return stock; }public void setStock(int stock) { this.stock = stock; }
}// 購物車類
public class ShoppingCart {private Map<Product, Integer> items = new HashMap<>();public void addItem(Product product, int quantity) {items.put(product, items.getOrDefault(product, 0) + quantity);}public void removeItem(Product product) {items.remove(product);}public double getTotalPrice() {double total = 0;for (Map.Entry<Product, Integer> entry : items.entrySet()) {total += entry.getKey().getPrice() * entry.getValue();}return total;}public Map<Product, Integer> getItems() {return items;}
}// 訂單類
public class Order {private String orderId;private List<Product> products;private double totalAmount;private OrderStatus status;public Order(String orderId, List<Product> products, double totalAmount) {this.orderId = orderId;this.products = products;this.totalAmount = totalAmount;this.status = OrderStatus.PENDING;}// Getters and setterspublic String getOrderId() { return orderId; }public List<Product> getProducts() { return products; }public double getTotalAmount() { return totalAmount; }public OrderStatus getStatus() { return status; }public void setStatus(OrderStatus status) { this.status = status; }
}// 訂單狀態枚舉
public enum OrderStatus {PENDING, PAID, SHIPPED, DELIVERED, CANCELLED
}// 系統測試用例
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;public class ShoppingSystemSystemTest {@Testpublic void testEndToEndShoppingFlow() {// 創建商品Product laptop = new Product("P001", "筆記本電腦", 5000.0, 10);Product mouse = new Product("P002", "鼠標", 50.0, 20);// 創建購物車ShoppingCart cart = new ShoppingCart();cart.addItem(laptop, 1);cart.addItem(mouse, 2);// 驗證購物車總價assertEquals(5100.0, cart.getTotalPrice(), 0.001);// 創建訂單String orderId = "ORD" + System.currentTimeMillis();Order order = new Order(orderId, cart.getItems().keySet().stream().collect(Collectors.toList()), cart.getTotalPrice());// 處理訂單支付order.setStatus(OrderStatus.PAID);assertEquals(OrderStatus.PAID, order.getStatus());// 更新庫存for (Map.Entry<Product, Integer> entry : cart.getItems().entrySet()) {entry.getKey().setStock(entry.getKey().getStock() - entry.getValue());}// 驗證庫存更新assertEquals(9, laptop.getStock());assertEquals(18, mouse.getStock());// 發貨order.setStatus(OrderStatus.SHIPPED);assertEquals(OrderStatus.SHIPPED, order.getStatus());// 確認收貨order.setStatus(OrderStatus.DELIVERED);assertEquals(OrderStatus.DELIVERED, order.getStatus());}
}

12.5 面向對象軟件的測試

12.5.1 類的測試

? ?類的測試關注類的屬性、方法和狀態。例如，測試一個銀行賬戶類：

public class BankAccount {private String accountNumber;private double balance;private AccountStatus status;public BankAccount(String accountNumber, double initialBalance) {this.accountNumber = accountNumber;this.balance = initialBalance;this.status = AccountStatus.ACTIVE;}public void deposit(double amount) {if (amount <= 0) {throw new IllegalArgumentException("存款金額必須大于0");}if (status != AccountStatus.ACTIVE) {throw new IllegalStateException("賬戶狀態異常，無法存款");}balance += amount;}public void withdraw(double amount) {if (amount <= 0) {throw new IllegalArgumentException("取款金額必須大于0");}if (status != AccountStatus.ACTIVE) {throw new IllegalStateException("賬戶狀態異常，無法取款");}if (amount > balance) {throw new InsufficientFundsException("余額不足");}balance -= amount;}public void close() {if (balance != 0) {throw new IllegalStateException("賬戶余額不為0，無法關閉");}status = AccountStatus.CLOSED;}// Getterspublic String getAccountNumber() { return accountNumber; }public double getBalance() { return balance; }public AccountStatus getStatus() { return status; }
}// 賬戶狀態枚舉
public enum AccountStatus {ACTIVE, CLOSED, FROZEN
}// 自定義異常
public class InsufficientFundsException extends RuntimeException {public InsufficientFundsException(String message) {super(message);}
}// 類的測試用例
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;public class BankAccountTest {private BankAccount account;@BeforeEachpublic void setUp() {account = new BankAccount("123456", 1000.0);}@Testpublic void testInitialState() {assertEquals("123456", account.getAccountNumber());assertEquals(1000.0, account.getBalance(), 0.001);assertEquals(AccountStatus.ACTIVE, account.getStatus());}@Testpublic void testDeposit() {account.deposit(500.0);assertEquals(1500.0, account.getBalance(), 0.001);}@Testpublic void testDepositNegativeAmount() {assertThrows(IllegalArgumentException.class, () -> account.deposit(-100.0));}@Testpublic void testWithdraw() {account.withdraw(300.0);assertEquals(700.0, account.getBalance(), 0.001);}@Testpublic void testWithdrawInsufficientFunds() {assertThrows(InsufficientFundsException.class, () -> account.withdraw(1500.0));}@Testpublic void testCloseAccount() {account.withdraw(1000.0); // 清空余額account.close();assertEquals(AccountStatus.CLOSED, account.getStatus());}@Testpublic void testCloseAccountWithBalance() {assertThrows(IllegalStateException.class, () -> account.close());}
}

12.5.2 交互測試

? ?交互測試驗證對象之間的協作和交互。例如，測試一個訂單處理系統中對象間的交互：

// 訂單類
public class Order {private String orderId;private List<OrderItem> items;private OrderStatus status;public Order(String orderId, List<OrderItem> items) {this.orderId = orderId;this.items = items;this.status = OrderStatus.PENDING;}public void processPayment(PaymentService paymentService) {double totalAmount = calculateTotalAmount();boolean paymentResult = paymentService.processPayment(totalAmount);if (paymentResult) {this.status = OrderStatus.PAID;}}private double calculateTotalAmount() {double total = 0;for (OrderItem item : items) {total += item.getProduct().getPrice() * item.getQuantity();}return total;}// Getters and setterspublic String getOrderId() { return orderId; }public List<OrderItem> getItems() { return items; }public OrderStatus getStatus() { return status; }
}// 訂單條目類
public class OrderItem {private Product product;private int quantity;public OrderItem(Product product, int quantity) {this.product = product;this.quantity = quantity;}// Getterspublic Product getProduct() { return product; }public int getQuantity() { return quantity; }
}// 商品類
public class Product {private String productId;private String name;private double price;public Product(String productId, String name, double price) {this.productId = productId;this.name = name;this.price = price;}// Getterspublic String getProductId() { return productId; }public String getName() { return name; }public double getPrice() { return price; }
}// 支付服務接口
public interface PaymentService {boolean processPayment(double amount);
}// 交互測試用例
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;
import static org.mockito.Mockito.*;public class OrderInteractionTest {@Testpublic void testOrderPaymentProcess() {// 創建模擬的支付服務PaymentService paymentService = mock(PaymentService.class);when(paymentService.processPayment(100.0)).thenReturn(true);// 創建商品和訂單條目Product product = new Product("P001", "手機", 100.0);OrderItem item = new OrderItem(product, 1);// 創建訂單Order order = new Order("ORD123", List.of(item));// 處理支付order.processPayment(paymentService);// 驗證結果assertEquals(OrderStatus.PAID, order.getStatus());verify(paymentService, times(1)).processPayment(100.0);}@Testpublic void testOrderPaymentFailure() {PaymentService paymentService = mock(PaymentService.class);when(paymentService.processPayment(100.0)).thenReturn(false);Product product = new Product("P001", "手機", 100.0);OrderItem item = new OrderItem(product, 1);Order order = new Order("ORD123", List.of(item));order.processPayment(paymentService);assertEquals(OrderStatus.PENDING, order.getStatus());verify(paymentService, times(1)).processPayment(100.0);}
}

12.5.3 繼承的測試

? ?繼承的測試關注子類與父類的關系，以及多態的正確性。例如，測試一個形狀繼承體系：

// 抽象形狀類
public abstract class Shape {public abstract double calculateArea();public abstract double calculatePerimeter();
}// 矩形類
public class Rectangle extends Shape {private double length;private double width;public Rectangle(double length, double width) {this.length = length;this.width = width;}@Overridepublic double calculateArea() {return length * width;}@Overridepublic double calculatePerimeter() {return 2 * (length + width);}
}// 正方形類
public class Square extends Rectangle {public Square(double side) {super(side, side);}
}// 圓形類
public class Circle extends Shape {private double radius;public Circle(double radius) {this.radius = radius;}@Overridepublic double calculateArea() {return Math.PI * radius * radius;}@Overridepublic double calculatePerimeter() {return 2 * Math.PI * radius;}
}// 繼承測試用例
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;public class ShapeInheritanceTest {@Testpublic void testRectangleArea() {Rectangle rectangle = new Rectangle(5.0, 3.0);assertEquals(15.0, rectangle.calculateArea(), 0.001);assertEquals(16.0, rectangle.calculatePerimeter(), 0.001);}@Testpublic void testSquareArea() {Square square = new Square(4.0);assertEquals(16.0, square.calculateArea(), 0.001);assertEquals(16.0, square.calculatePerimeter(), 0.001);}@Testpublic void testCircleArea() {Circle circle = new Circle(2.0);assertEquals(Math.PI * 4.0, circle.calculateArea(), 0.001);assertEquals(2 * Math.PI * 2.0, circle.calculatePerimeter(), 0.001);}@Testpublic void testPolymorphism() {Shape rectangle = new Rectangle(5.0, 3.0);Shape square = new Square(4.0);Shape circle = new Circle(2.0);assertEquals(15.0, rectangle.calculateArea(), 0.001);assertEquals(16.0, square.calculateArea(), 0.001);assertEquals(Math.PI * 4.0, circle.calculateArea(), 0.001);}
}

12.6小結

? ?軟件測試是軟件開發過程中不可或缺的環節，它貫穿于整個軟件生命周期。通過本章的學習，我們了解了軟件測試的概念、過程模型、測試方法以及面向對象軟件的測試技術。合理運用各種測試方法和技術，能夠有效發現軟件中的缺陷，提高軟件質量，確保軟件滿足用戶需求。在實際項目中，應根據項目特點和需求，選擇合適的測試策略和方法，制定全面的測試計劃，以保證軟件的可靠性和穩定性。