You can import a CSV file with a test record, hence you use the new contact for your test send.
Note: your CSV file would need these fields: Contact Key, DeviceID, Platform, System Token
I put these steps here for your reference:
- Go to Mobile Push: Mobile Studio >> Mobile Push
- On the top right corner: click Add Contacts.
- Select the destination for the imported contacts.
- Select the file to upload.
- Before uploading, certify whether you have opt-in permission from contacts in the file.
- Click Next.
- Select the application to associate with the contacts.
- Click Next.
- Map the column headings in the file to the supported MobilePush columns
- Click Next.
- Review the import mapping. Make sure that the column headings match the data in the columns. Click Back to change.
- Enter your email address for notification when the import completes.
- Click Finish.
Reference: Import Contacts into MobilePush