Thoughts about software development

Integration test is something that tests a functionality that is dependant on a external system e.g. a database, HTTP API or message queue. Integration vs unit tests The line is thin in my opinion. The integration part can be faked or a embedded services can be used in place of the actual integration point and with these solutions the interaction with the external system is bounded in the test context and the tests can be executed in isolation so they are very much like unit tests. The only difference with this type of integration test and unit test is that the startup time of the embedded or faked system usually takes some seconds and that adds total execution time of the tests. Even though the total test exection time is longer all the tests need to pass and all the cases need to be covered whether there's external systems involved or not so the importance is equal between the test types. This is why I wouldn't separate unit and integration tests from each other within the co

Unit tests are the developers number one safety net. Let that sink in. This is the number one reason for writing unit tests. Unit tests are written by developers for developers to ensure that the code works as expected and handles happy and sad paths correctly. With enough unit test coverage the tests enable a safe environment for refactoring and rewriting code. Unit test scope Unit test should test a single thing, a method or function call and it should test only one use case within. In other words a unit test should test a function with a single input. This is a important guideline to understand. When a unit test tests a function with single input it makes the test isolated, repeatable and predictable. Example of good tests: @Test fun findsAddress() {   val address = findAddress("Stevens street 35", "Southport", "Australia")   assertThat(address).isNotNull() } @Test fun doesNotFindAddress() {   val address = findAddress("Stevens street 697", &q