Is there a test account for Instagram

You can create a Facebook test user, Login on Facebook and then sign up with Facebook test user on Instagram.com This works for me!

Instagram does not provide test accounts in the same sense Facebook does.

Instagram provides an API Console (powered by Apigee) to test your API calls. For calls requiring an authenticated user you would need to use an existing Instagram account.

UPDATE Instagram now provides a Sandbox mode for all new applications.

From Instagram

Apps created on or after Nov 17, 2015 can take advantage of Sandbox mode right away. Apps created before this date will only be able to use Sandbox mode after June 1, 2016, but can still start submitting for review. On June 1, 2016 any app that has not been reviewed and approved will be set to sandbox mode.

More info in the Instagram docs.