Today, the use of dependency containers is widespread. The constructor of your classes accepts instances of other classes, they depend on other classes, etc. And the dependency container manages the construction of the entire instance tree.
This system has its price. For example, during testing, you must create instances of all the dependencies of a class in order to test this class. You can use something like Moq for this task. But in this case, there is a problem with class changes. If you want to add or remove any constructor parameter, you will also have to change the tests, even if this parameter does not affect them.
There is another task that we want to solve during testing. Let's say we want to test the work of not one isolated class, but the joint work of several classes in some part of our system. Our dependency container creates a whole tree of instances of various classes. And you want to test the whole tree. Let's see how we can do this, what obstacles we will face and how we can overcome them.
