PHPUnit 4.8 Mock mysql database interface - php

Question

Good afternoon,
I have a bunch of legacy code that uses the old mysql library (mysql_query($sql) for example) and am trying to test it with PHPUnit (4.8 is the latest that will run on the server for various reasons).
Does anyone know how to mock this database connection so that it can return predetermined results when predetermined queries are run? I have tried using getConnection() (as per the docs here: http://devdocs.io/phpunit~4/database) to no avail.
For example I have this class:
class Raffle {
...
public static function loadAll($filter=""){
//$filter = mysql_real_escape_string($filter); // protect against SQL injection
$raffles = []; // the array to return
$sql = "SELECT * FROM raffles $filter;"; // include the user filter in the query
$query = mysql_query($sql);
//echo mysql_error();
while($row = mysql_fetch_assoc($query)){
$raffles[] = Raffle::loadFromRow($row); // generate the raffe instance and add it to the array
}
return $raffles; // return the array
}
...
}
(The mysql_connect() call is done in a file called db.php which is loaded on every page that it is needed and not in the class file itself.)
Thanks in advance.

Answer 1

For anyone else stuck in this situation I found that building a mock for PDO that contains a fallback to the functional api allowed me to migrate the code to a Testable OO based model while still using the old mysql library under the hood.
For example:
// the basic interfaces (function names taken from PDO
interface DBConnAdapter {
public function query($sql);
}
// since PDO splits connections and statements the adapter should do the same
interface DBQueryAdapter {
public function num_rows();
public function fetch_assoc();
}
...
class DBAdapter implements DBConnAdapter {
public function query($sql){
$query = mysql_query($sql); // run the query using the legacy api
return $query ? new QueryAdapter($query) : false; // return a new query adapter or false.
}
}
...
// an example of a basic mock object to test sql queries being sent to the server (inspired by mockjax :-) )
class DBMock implements DBConnAdapter {
public $queries = []; // array of queries already executed
public $results = []; // array of precomputed results. (key is SQL and value is the returned result (nested array))
public function query($sql) {
if($this->results[$sql]){
$query = new DBQueryMock($sql, $this->results[$sql]); // a mock of PDOStatement that takes the sql it ran and the results to return
$queries[] = $query; // add the query to the array
return $query; // return the query
}
return false; // we do not know the statement so lets pretend it failed
}
// add a result to the list
public function add_single_result($sql, $result){
// check if the index was set, if not make an array there
if(!isset($this->results[$sql])) $this->results[$sql] = [];
// add the result to the end of the array
$this->results[$sql][] = $result;
// return its index
return count($this->results[$sql]) - 1;
}
}
Admittedly this is not an ideal solution as it requires modifying the code to support the adapter objects and removes some functionality (such as mysql_real_escape_string), but it worked....
If you have a better solution please share :-) Thanks!