Unit testing tests one unit of functionality and it keeps dependencies minimal and isolated from the environment, including Spring. We can use simplified alternatives for dependencies such as stubs and/or mocks.
In unit testing, there must not be any external dependencies, because external dependencies aren't available since we are testing a unit. So, remove links with dependencies. The test shouldn't fail because of external dependencies. You can remove external dependencies of your implementation for testing purposes by using stubs and mocks. Stubs create a simple test implementation and a mock dependency class generated at startup-time using a mocking framework.
Let's see the following diagram related to the unit testing example: ...