指示没有透支的python unittest错误

我一直在进行测试，每次运行代码时，都会显示以下错误代码：

测试\u储蓄\u账户\u不能\u提取\u超过\u当前\u余额失败 在第48行，在 测试储蓄账户不能提取超过当前余额的存款 self.assertEquals（消息“不能超过当前帐户提取” 余额'，msg='No overdrafts'）断言错误：无透支**

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因为您的默认余额是500，您的金额是1500，所以它将返回的字符串是“不能超过最低帐户余额提取”，而不是您期望的“不能超过当前帐户余额提取”

您需要问一个特定的问题。

class BankAccount:
    def withdraw(self):
        pass

    def deposit(self):
        pass

class SavingsAccount(BankAccount):
    def __init__(self, balance=500):
        self.balance = balance

    def deposit(self, amount):
        if (amount <= 0):
            return "Invalid deposit amount"
        else:
            self.balance += amount
        return self.balance

    def withdraw(self, amount):
        if(amount <= 0):
            return "Invalid withdraw amount"
        elif(self.balance <= 500):
            return "Cannot withdraw beyond the minimum account balance"
        elif(amount > self.balance):
            return "Cannot withdraw beyond the current account balance"
        else:
            self.balance -= amount
            return self.balance    


class CurrentAccount(BankAccount):
    def __init__(self, balance=0):
        self.balance = balance

    def deposit(self, amount):
        if (amount <= 0):
            return "Invalid deposit amount"
        else:
            self.balance += amount
            return self.balance

    def withdraw(self, amount):
        if (amount <= 0):
            return "Invalid withdraw amount"
        elif (amount >= self.balance):
            return "Cannot withdraw beyond the current account balance"
        else:
        self.balance -= amount
        return self.balance

import unittest

class CurrentAccountTestCases(unittest.TestCase):
    def setUp(self):
        self.ca = CurrentAccount()

    def tearDown(self):
        del self.ca

    def test_current_account_is_instance_of_bank_account(self):
        self.assertTrue(isinstance(self.ca, BankAccount), msg='CurrentAccount is not a subclass of BankAccount')

    def test_current_account_can_deposit_valid_amounts(self):
        balance = self.ca.deposit(1500)
        self.assertEquals(balance, 1500)

    def test_current_account_cannot_withdraw_more_than_current_balance(self):
      message = self.ca.withdraw(1500)
      self.assertEquals(message, 'Cannot withdraw beyond the current account balance', msg='No overdrafts')

    def test_current_account_can_withdraw_valid_cash_amounts(self):
        self.ca.deposit(23001)
        self.ca.withdraw(437)
        self.assertEquals(self.ca.balance, 22564, msg='Incorrect balance after withdrawal')

class SavingsAccountTestCases(unittest.TestCase):
    def setUp(self):
self.sa = SavingsAccount()

    def tearDown(self):
      del self.sa

    def test_savings_account_is_instance_of_bank_account(self):
      self.assertTrue(isinstance(self.sa, BankAccount), msg='SavingsAccount is not a subclass of BankAccount')

    def test_savings_account_can_deposit_valid_amounts(self):
      init_balance = self.sa.balance
      balance = self.sa.deposit(1500)
      self.assertEquals(balance, (1500 + init_balance), msg='Balance does not match deposit')

    def test_savings_account_cannot_withdraw_more_than_current_balance(self):
      message = self.sa.withdraw(1500)
      self.assertEquals(message, 'Cannot withdraw beyond the current account balance', msg='No overdrafts')

    def test_savings_account_can_withdraw_valid_amounts_successfully(self):
      self.sa.deposit(2300)
      self.sa.withdraw(543)
      self.assertEquals(2257, self.sa.balance, msg="Incorrect balance after withdrawal")