Braintree Unsuccessful credit card verification is not working for my code

I am trying to test braintree single payment. All works fine and the code makes a transactions which I can see in the sandbox and also from response code.

But the problem is when I try to use one their 'Unsuccessful credit card numbers' it still process the transactions and gives me success as a response.

Here is the code I am using for making transaction.

$result = \Braintree\Transaction::sale([
        'amount' => $amount,
        'paymentMethodNonce' => $nonce,
        'options' => [
            'submitForSettlement' => true
         ]
      ]);

This code never gives error unsuccessful credit card verification number. I tried to use verifyCard=true in the options array and gives me error.