Principles of writing a good unit test
Unit testing principles
I usually spend time thinking good names for variables and helper functions that build the state. Trivial refactoring can cause complication errors and failures in the tests. And that means bad design. What is integration testing? We will see that writing unit tests and generating testable code is not just about making testing less troublesome, but about making the code itself more robust, and easier to maintain. A single test should not depend on running other tests before it, nor should it be affected by the order of execution of other tests. Not implementable to logical operators. Use Data Helper classes that can setup this data for re-usability. I love computers, programming and solving problems everyday. When you are not yet confident, keep going. It is hard to predict and maintain.
As mentioned earlier, a good place to look for more information on this subject, writing unit tests in general, and much more, have a look at the Clean Code book. Its reasonable to have tests of this type if you know or expect that your dependency is unstable or has no tests, but at the same time if you know that then maybe thats a bad dependency.
Test everything that can possibly break. All of these including setup, the actual test and tear down should execute really fast milliseconds as you may have thousands of tests in your entire project.
But what trust really means? They can easily introduce tight coupling and make our code untestable.
Unit test boundary
Self-validating Tests must be self-validating means — each test must be able to determine that the output is expected or not. Tests for security with users having different roles - behavior may be different based on user's role. Test should be readable like a book; so write the comments in Asserts. Avoiding duplication in tests creates tests that are difficult to read and understand: In other words, having to change similar tests is preferable to not understanding one non-duplicated test when it fails. By writing the tests first, I am forced to describe in my test case the behavior rather than the implementation because I have no implementation yet. Good unit tests should be reproducible and independent from external factors such as the environment or running order. Excellent — the method is testable, but how about its clients? What if a set of tests need some common data? This is normally done using asserts such as assertTrue or assertEquals, which will cause the test to pass or fail depending on their results. If someone reads your test name, it should make sense to them why you are writing the test. In best case scenario, you should be able to run any one test at any time, in any order. RunWith JUnit4.
Instead of creating our fake objects by hand, we can use the framework to create them with only a few API calls. It must determine it is failed or pass.
If the answer is yes, then I have a test suite that I can trust.
based on 120 review