Fix MySQLi SSL flags handling to explicitly set MYSQLI_CLIENT_SSL if …

[EreMaijala]

…use_ssl is set.

Signed-off-by: Ere Maijala ere.maijala@helsinki.fi

Q	A
Documentation	no
Bugfix	yes
BC Break	no
New Feature	no
RFC	no
QA	yes

Description

This fixes an issue where setting use_ssl to true alone doesn't actually make the connection secure. It is only made secure if any of the client_key, client_cert, ca_cert, ca_path or cipher is also set to a non-empty value.

To reproduce the problem prior to this fix do something like this:

use Laminas\Db\Adapter\Adapter;
$adapter = new Adapter(
    [
        'driver' => 'mysqli',
        'hostname' => 'localhost',
        'username' => 'user',
        'password' => 'password',
        'database' => 'test',
        'use_ssl' => true
    ]
);
$statement = $adapter->createStatement("SHOW SESSION STATUS LIKE 'Ssl_cipher'");
foreach ($statement->execute() as $res) {
    print_r($res);
}

Expected: a non-empty value for Ssl_cipher
Actual: Ssl_cipher is empty
Tested with: PHP 7.2.20

The patch moves mysqli class creation in the Connection class to a helper method to make it easier to test the class and adds a couple of tests that verify the connection parameters using mock objects. The failed connection test is moved last since it sets connect_error property in mysqli, and I couldn't find a simple way to mock or override it later on (trying to mock the __get method causes a warning with PHPUnit).

[kris-sum]

This will close #53