Does the following method have single responsibility?
Validation of input parameters are at the beginning of the method. If the method has code after validation, then it has not a single responsibility. How can we separate validation code for input parameters and rest of the code?
Let’s create a class that it stores a list of values and it can compute some value based on stored values. Internally elements are stored in a List. When class is created form the list of values, we can create a collector for it. There is no need for public constructor.
Cumulative time is increasing by executing tests through time. Is every lost second important?
Start practicing yoga.
Unit test is executed in less than half of the second. When we have an integration test which is using a repository that is connected to a database it will be executed in several seconds. With a repository, that has an implementation in-memory, tests will be executed faster. There are also other benefits.
Can entities have only attributes that are data values and aren’t collections? What is alternative?
You have a test coverage 90% or more but not 100%. You have tests that cover all exceptional cases. What about code that is not covered with tests?
Without tests, you can’t know how the production code works. When you write a test for the production code, you define how the production code works. Latter you can easily change the production code with refactoring or rewrite. Do test have to be written as good as the production code or better?
Entities can be changed. Why represent them as immutable objects?