Fix unit tests

[afilippov1985]

No description provided.

[afilippov1985]

Travis is broken again

[afilippov1985]

Fix "Expiration (exp) time must be a unix time stamp"

Here ctype_digit($jwt['exp']) evals to false when $jwt['exp'] > PHP_INT_MAX

// on 32-bit
$d = 99999999900;
var_dump($d, ctype_digit($d));
//double(99999999900) bool(false) 

// BUT
$d = '99999999900';
var_dump($d, ctype_digit($d));
//string(11) "99999999900" bool(true) 

// on 64-bit
$d = 99999999900;
var_dump($d, ctype_digit($d));
//int(99999999900) bool(true) 

$d = '99999999900';
var_dump($d, ctype_digit($d));
//string(11) "99999999900" bool(true) 

[afilippov1985]

May be we should also check that access_token key exists in array.

[afilippov1985]

ping @bshaffer

[bshaffer]

We should make this PR to master as the develop branch is no longer being used.

Also, the tests are passing as-is, so I'm not entirely sure what this fixes.

[afilippov1985]

I'll make a few smaller PRs.