Unit test a plugin in Drupal 8

I want to add a small unit test to a migrate plugin for a migration I am building. I looked for some examples but did not find much for unit tests of a plugin.

I want to run some assertions when the plugin is instantiated and check its values in a unit test. Is PluginTestBase the class to use? Can I not simply run a test without bootstrapping Drupal?

class EndpointTest extends PluginTestBase {   // not sure what to do here }