Can you provide examples of testing that correspond to different levels of the testing pyramid?

The testing pyramid is a concept that describes different levels of automated testing and their proportion in terms of quantity and complexity.

Examples of tests for each level:

• Unit tests — test individual functions or methods. They are fast and isolated.

  @Test
  public void testSum() {
      assertEquals(5, Calculator.sum(2, 3));
  }
  

• Integration tests — test the interaction between multiple components or modules. For example, testing DAO operations with a database.

• System tests — test the entire system, including the user interface. For example, an automated UI test using Selenium that checks a login scenario.

The pyramid recommends having more unit tests, fewer integration tests, and even fewer system tests to ensure a balance between testing speed and coverage.