is it possible to deploy the classes and respected test classes one dev org to another dev org using Change-Set.
You can move metadata only between the production org and its sandboxes. You can’t move changes between two production orgs or Developer Editions.
You can take advantage of ANT or Eclipse Force.com ide instead.
Can have look into this link for more info. https://trailhead.salesforce.com/en/alm_deployment/alm_tools