使用Pytest测试Python银行代码时无测试执行问题求助

我写了一段银行相关的Python代码，主代码运行完全正常，但用Pytest跑测试时一直提示“无测试执行”。我是编程新手，现在要完成课程要求的TDD学习，没法延后，附上主代码和测试代码，求帮忙排查问题。

主代码（bank_program.py） #

import datetime

tday = datetime.date.today()
balance = 1000.0
amount = float
transaction_list = []


class Account(amount):

    def get_balance(self):
        print("\n  This is your account balance: " + str(balance))

    def deposit(self, amount):
        global balance
        amount = float(input("\n  How much would you like to deposit? "))
        if amount > 10000:
            print("\n  Do you want to swim in the vualt? ")
        transaction_list.append("You deposited " + str(amount))
        balance = balance + amount
        print("\n  You're balance is now " + str(balance))


    def withdrawl(self, amount):
        global balance
        amount = float(input("\n  How much do you wanna take out? "))
        while amount > balance:
            amount = float(input("\n  You don't have enough funds. Enter a new value "))
        transaction_list.append("\n  You withdrew " + str(amount))
        balance = balance - amount
        print("\n  You're balance is now " + str(balance))   

class Transaction(amount):

    def transaction(self):
        print("\n")
        print("  " + str(card_number) + " " + str(tday))
        print("\n  Recipt: HM21-1926\n")
        print("\n  Account: Chequing. Primary\n")

        print("\n  Here is your transaction history!\n")
        for i in transaction_list:
            print(i)

        print("\n  Account Balance: " + str(balance))
        print("\n  Limited time offer: get a personal loan starting at Prime + 1.99%*")
        print("\n  Offer valid until September 2, 2022.")
        print("\n  Conditions apply & approval required. Ask us for details.\n")

    account = Account()
    transaction = Transaction()


if __name__ == "__main__":
    mike_lane = Account()
    print(repr(mike_lane))
    print(str(mike_lane))

测试代码（原版本） #

import bank_program

def test_deposit():

    account = Account(100)
    assert balance.amount == 1100

def test_depos():
    with pytest.raises(ValueError):
        assert amount = Account("ABC")


def test_transactions():
    account = Account(100)
    assert tday() >= now

问题排查与修复步骤 #

1. 直接导致“无测试执行”的测试代码问题 #

• 测试代码未导入pytest，且引用的Account、balance、tday未从bank_program模块中导入，Pytest无法识别有效测试逻辑。
• 测试文件名需符合Pytest规则：必须以test_开头（比如test_bank.py），否则Pytest不会扫描到该文件。

2. 主代码设计缺陷（影响测试可行性） #

• 全局变量滥用：balance、transaction_list是全局变量，所有账户共享同一状态，无法单独测试单个账户的行为。
• 不合理继承：Account类继承float毫无意义，未利用类的封装特性。
• 依赖手动输入：deposit、withdrawl方法直接调用input()获取输入，导致测试时需要手动交互，无法自动化执行。
• 未定义变量：Transaction类中引用的card_number未定义，运行时会直接报错。

3. 修复后的可测试代码示例 #

修改后的主代码（bank_program.py）

import datetime

class Account:
    def __init__(self, initial_balance=1000.0):
        self.balance = initial_balance
        self.transaction_list = []

    def get_balance(self):
        return self.balance

    def deposit(self, amount):
        if not isinstance(amount, (int, float)) or amount <= 0:
            raise ValueError("存款金额必须是正数")
        if amount > 10000:
            print("\n  Do you want to swim in the vault? ")
        self.transaction_list.append(f"You deposited {amount}")
        self.balance += amount
        return self.balance

    def withdrawal(self, amount):
        if not isinstance(amount, (int, float)) or amount <= 0:
            raise ValueError("取款金额必须是正数")
        if amount > self.balance:
            raise ValueError("余额不足")
        self.transaction_list.append(f"You withdrew {amount}")
        self.balance -= amount
        return self.balance

class Transaction:
    def __init__(self, account, card_number):
        self.account = account
        self.card_number = card_number
        self.tday = datetime.date.today()

    def generate_receipt(self):
        receipt = [
            f"\n  {self.card_number} {self.tday}",
            "\n  Receipt: HM21-1926\n",
            "\n  Account: Chequing. Primary\n",
            "\n  Here is your transaction history!\n"
        ]
        receipt.extend(self.account.transaction_list)
        receipt.append(f"\n  Account Balance: {self.account.get_balance()}")
        receipt.extend([
            "\n  Limited time offer: get a personal loan starting at Prime + 1.99%*",
            "\n  Offer valid until September 2, 2022.",
            "\n  Conditions apply & approval required. Ask us for details.\n"
        ])
        return "\n".join(receipt)

if __name__ == "__main__":
    mike_lane = Account()
    print(mike_lane.get_balance())
    mike_lane.deposit(500)
    print(mike_lane.get_balance())

可执行的测试代码（test_bank.py）

import pytest
from bank_program import Account, Transaction
import datetime

def test_deposit():
    account = Account(1000.0)
    account.deposit(100)
    assert account.get_balance() == 1100.0

def test_deposit_invalid_amount():
    account = Account()
    with pytest.raises(ValueError):
        account.deposit(-500)
    with pytest.raises(ValueError):
        account.deposit("ABC")

def test_withdrawal():
    account = Account(1000.0)
    account.withdrawal(300)
    assert account.get_balance() == 700.0

def test_withdrawal_insufficient_funds():
    account = Account(500.0)
    with pytest.raises(ValueError):
        account.withdrawal(1000)

def test_transaction_receipt():
    account = Account()
    account.deposit(200)
    transaction = Transaction(account, "1234-5678-9012-3456")
    receipt = transaction.generate_receipt()
    assert "You deposited 200" in receipt
    assert "Account Balance: 1200.0" in receipt
    assert str(datetime.date.today()) in receipt

4. 执行测试的正确步骤 #

1. 确保测试文件名为test_bank.py，主代码文件为bank_program.py，放在同一目录下。
2. 安装Pytest：pip install pytest
3. 运行测试：在终端执行pytest，Pytest会自动扫描并执行所有测试用例。

内容的提问来源于stack exchange，提问作者HyperionSmith