We know that php is a server side scripting language. So we will need a server with the php parser to parse/test our code.
How are you doing that. Do you upload it to a server for testing or did you instal php and the server (apache) on your computer (localhost)

I upload it to my server, and usualy name it filenametest.php or something

I don't run my own server so I test all server-side scripts through the web host. Testing your scripts locally is deemed good practice, but the logistics involved in running your own server beats down the practicality value at the moment. Also, sometimes your local server may run scripts differently than your actual host.

I wouldn't test them locally. Maybe if I wasn't too lazy to install Apache, but the web server could still be configured differently, as chinfo says.

I always test my scripts locally before sending them anywhere. If your server is configured differently, then change the configuration to match the host. You can find all the information you should need to match by calling phpinfo().

I always test them locally.
I have Apache, PHP, and MySQL installed, so i can test them

I always upload them and test them, I always expect at least one error the first time. Maybe when I get a good enough computer I'll install PHP in it.

You don't need a good computer to run a simple webserver and PHP/MySQL, provided you are only using locally. You could use a 486 if you wanted.

Well I do need a good connection 'cause I've had other people connect to my pc using CesarFTP but it doesn't work after a while.

i use a home webserver, i installed apache triad, which installs apache, php mysql and a bunch of other stuff, im building my entire site on it b4 i upload it, plus its nice and fast