Is it correct to call and use this as a stub or mock?

I am using handwritten forgeries for the demo application, but I am not sure if I am using the mock appropriately. Here's my code below:

[Fact]
    public void TransferFund_WithInsufficientAccountBalance_ThrowsException()
    {
        IBankAccountRepository stubRepository = new FakeBankAccountRepository();
        var service = new BankAccountService(stubRepository);

        const int senderAccountNo = 1, receiverAccountNo = 2;
        const decimal amountToTransfer = 400;

        Assert.Throws<Exception>(() => service.TransferFund(senderAccountNo, receiverAccountNo, amountToTransfer));
    }

    [Fact]
    public void TransferFund_WithSufficientAccountBalance_UpdatesAccounts()
    {
        var mockRepository = new FakeBankAccountRepository();
        var service = new BankAccountService(mockRepository);
        const int senderAccountNo = 1, receiverAccountNo = 2;
        const decimal amountToTransfer = 100;

        service.TransferFund(senderAccountNo, receiverAccountNo, amountToTransfer);

        mockRepository.Verify();
    }

      

        
        
        
      

    

Double test:

public class FakeBankAccountRepository : IBankAccountRepository
{
    private List<BankAccount> _list = new List<BankAccount>
    {
        new BankAccount(1, 200),
        new BankAccount(2, 400)
    };

    private int _updateCalled;

    public void Update(BankAccount bankAccount)
    {
        var account = _list.First(a => a.AccountNo == bankAccount.AccountNo);
        account.Balance = bankAccount.Balance;
        _updateCalled++;
    }

    public void Add(BankAccount bankAccount)
    {
        if (_list.FirstOrDefault(a => a.AccountNo == bankAccount.AccountNo) != null)
            throw new Exception("Account exist");

        _list.Add(bankAccount);
    }

    public BankAccount Find(int accountNo)
    {
        return _list.FirstOrDefault(a => a.AccountNo == accountNo);
    }

    public void Verify()
    {
        if (_updateCalled != 2)
        {
            throw new Xunit.Sdk.AssertException("Update called: " + _updateCalled);
        }
    }
}

      

        
        
        
      

    

the second test creates a fake and refers to it as a mock, then it calls the validator method. Is this approach right or wrong?