【设计模式】JAVA Design Patterns——Arrange/Act/Assert（安排/执行/断言模式）

public class Cash {
 
  private int amount;
 
  Cash(int amount) {
    this.amount = amount;
  }
 
  void plus(int addend) {
    amount += addend;
  }
 
  boolean minus(int subtrahend) {
    if (amount >= subtrahend) {
      amount -= subtrahend;
      return true;
    } else {
      return false;
    }
  }
 
  int count() {
    return amount;
  }
}

class CashAAATest {
 
  @Test
  void testPlus() {
    //Arrange
    var cash = new Cash(3);
    //Act
    cash.plus(4);
    //Assert
    assertEquals(7, cash.count());
  }
 
  @Test
  void testMinus() {
    //Arrange
    var cash = new Cash(8);
    //Act
    var result = cash.minus(5);
    //Assert
    assertTrue(result);
    assertEquals(3, cash.count());
  }
 
  @Test
  void testInsufficientMinus() {
    //Arrange
    var cash = new Cash(1);
    //Act
    var result = cash.minus(6);
    //Assert
    assertFalse(result);
    assertEquals(1, cash.count());
  }
 
  @Test
  void testUpdate() {
    //Arrange
    var cash = new Cash(5);
    //Act
    cash.plus(6);
    var result = cash.minus(3);
    //Assert
    assertTrue(result);
    assertEquals(8, cash.count());
  }
}