Sorry... expected output should be

array(4) {
  [0]=>
  string(15) "Name,Desc,Email"
  [1]=>
  string(4) "Alex"
  [2]=>
  string(18) "Is a PHP
developer
"
  [3]=>
  string(16) "alex@example.com"
}

The problem can also be shown with the example from the Wikipedia page (http://en.wikipedia.org/wiki/Comma-separated_values):

$s2=<<<EOD
Year,Make,Model,Description,Price
1997,Ford,E350,"ac, abs, moon",3000.00
1999,Chevy,"Venture ""Extended Edition""","",4900.00
1999,Chevy,"Venture ""Extended Edition, Very Large""","",5000.00
1996,Jeep,Grand Cherokee,"MUST SELL!
air, moon roof, loaded",4799.00
EOD;

$lines=str_getcsv($s2,"\n");
print_r($lines);

It outputs:
Array
(
    [0] => Year,Make,Model,Description,Price
    [1] => 1997,Ford,E350,"ac, abs, moon",3000.00
    [2] => 1999,Chevy,"Venture ""Extended Edition""","",4900.00
    [3] => 1999,Chevy,"Venture ""Extended Edition, Very Large""","",5000.00
    [4] => 1996,Jeep,Grand Cherokee,"MUST SELL!
    [5] => air, moon roof, loaded",4799.00
)

But it should output:
Array
(
    [0] => Year,Make,Model,Description,Price
    [1] => 1997,Ford,E350,"ac, abs, moon",3000.00
    [2] => 1999,Chevy,"Venture ""Extended Edition""","",4900.00
    [3] => 1999,Chevy,"Venture ""Extended Edition, Very Large""","",5000.00
    [4] => 1996,Jeep,Grand Cherokee,"MUST SELL!
air, moon roof, loaded",4799.00
)

to split the string in to record lines I used a regular expression that makes sure not to split inside of double quotes instead of using the str_getcsv. Then I used the str_getcsv on the line.

example

$s2=<<<EOD
Year,Make,Model,Description,Price
1997,Ford,E350,"ac, abs, moon",3000.00
1999,Chevy,"Venture ""Extended Edition""","",4900.00
1999,Chevy,"Venture ""Extended Edition, Very Large""","",5000.00
1996,Jeep,Grand Cherokee,"MUST SELL!
air, moon roof, loaded",4799.00
EOD;

lines = preg_split('/[\r\n]{1,2}(?=(?:[^\"]*\"[^\"]*\")*(?![^\"]*\"))/',$s2);

it outputs
Array (
 [0] => Year,Make,Model,Description,Price
 [1] => 1997,Ford,E350,"ac, abs, moon",3000.00
 [2] => 1999,Chevy,"Venture ""Extended Edition""","",4900.00
 [3] => 1999,Chevy,"Venture ""Extended Edition, Very Large""","",5000.00
 [4] => 1996,Jeep,Grand Cherokee,"MUST SELL! air, moon roof, loaded",4799.00 
) 

to further convert 

$data = array();
foreach($lines as $row) {
 $data[] = str_getcsv($row);
}

print_r($data);

which will output

Array (
 [0] => Array (
   [0] => Year
   [1] => Make
   [2] => Model
   [3] => Description
   [4] => Price
 )
 [1] => Array (
   [0] => 1997
   [1] => Ford
   [2] => E350
   [3] => ac, abs, moon
   [4] => 3000.00
 )
 [2] => Array (
   [0] => 1999
   [1] => Chevy
   [2] => Venture "Extended Edition"
   [3] =>
   [4] => 4900.00
 )
 [3] => Array (
   [0] => 1999
   [1] => Chevy
   [2] => Venture "Extended Edition, Very Large"
   [3] => 
   [4] => 5000.00
 )
 [4] => Array (
   [0] => 1996
   [1] => Jeep
   [2] => Grand Cherokee
   [3] => MUST SELL! air, moon roof, loaded
   [4] => 4799.00
 )
)

$csvTestStr = 'mg3150 manual,12,-61%,6,-54%,50%,8.0,1.0,
"canon powershot sx400 is 16mp, 30x zoom mini bridge camera w/ case & sd card",12,?,6,?,50%,50,1.0,
canon printer mg6450,12,20%,6,,50%,-10,1.0,
canon pixma 3150 wireless setup,12,-48%,6,-33%,50%,10,1.0,
mg3150 manual,12,-61%,6,-54%,50%,8.0,1.0,
"canon powershot sx400 is 16mp, 30x zoom mini bridge camera w/ case & sd card",12,?,6,?,50%,50,1.0,
canon printer mg6450,12,20%,6,,50%,-10,1.0,
canon pixma 3150 wireless setup,12,-48%,6,-33%,50%,10,1.0,';
        //$fields = str_getcsv($row,"/n"); #fail
        $rows = preg_split('/[\r\n]{1,2}(?=(?:[^\"]*\"[^\"]*\")*(?![^\"]*\"))/', $csvTestStr); #split rows properly
        $this->assertTrue(count($rows) === 8);
        foreach ($rows as $row) {
            $fields = str_getcsv($row,',');
            $this->assertTrue(count($fields) === 9);
            if (count($fields) !== 9) {
                debug($fields);
            }
        }

str_getcsv() is designed to parse a single CSV record into fields (what works as expected, see <http://3v4l.org/f1DXO>).

If \n as given as delimiter, it splits the string at the line endings, and also heeds the enclosing parameter, but only if that characters encloses the complete field (in this case one or more lines). This also works as expected, see <http://3v4l.org/UfsLi>.

This *IS* a bug.  Here is an example of valid quotation marks and new lines which illustrates the real problem:

https://3v4l.org/HAJh1

Again, str_getcsv() is supposed to parse a *single* CSV record
(aka. line), exactly like fgetcsv() does.  How to split CSV
contents into records is left to the programmer.
<https://3v4l.org/D8Mqt> uses concrete knowledge of the input data
to correctly do that.