How can i test that my paypal button is working properly

Are you pertaining to this button?

If you want to test if your PayPal payment field set up is working, you can first try it using your PayPal sandbox account. If you don't have a sandbox account yet, you can create it through this website, https://developer.paypal.com/developer/accounts. You can create a sandbox account under Dashboard tab of that page.

But first you need to log in your existing PayPal account.

Here's a guide I found over the internet: Creating Sandbox Test Accounts

Notice on the screenshots I have above, there are two types of account that you can create, one if Merchant account. Merchant account is the seller's account, meaning you will have to place the email address of your merchant account here:

And the other one is Buyer's account. Buyer's account will be used when you're testing a purchase. If you click the Pay with PayPal button, you will be redirected to the page shown on the image below.

Basically, you need to have a sandbox merchant account and a sandbox buyer's account. So you can make a test payment with PayPal. 

One last thing, please don't forget to make the PayPal payment field in sandbox mode before making any test or else it this won't work, since it assume that you're running a live PayPal account and not a Sandbox account.

I hope this helps. Let us know if you need assistance with any of the instruction given above. Thank you.