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Tests implementation
Unit tests
JUnit tests are the simple and fast tests that use mocks to check simple, single functionality. You should write JUnit to check every function that you use in your code. JUnit must be fast, it should be matters of seconds to run that test.
Naming param is <className>Test.java
Integration tests
Integration tests are here to check whenever the functions that you use in code work well together. Those tests may take longer to run. In maven they are run in integration-test phase.
Naming param is <className>IT.java, or <className>IntegrationTest.java.
Acceptance tests
You write acceptance tests to check if your code fulfill, the requirements of project.
Naming param is <className>Acceptancetest.java, we run these tests in integration-test phase.