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I am in the process of writing some unit tests. In particular I want to test some private methods.
So far the I have come up with using.
#define private public But I am not happy with this as it will destroy all encapsulation from the point of view of the unit test.
What methods do you use to unit-test private methods.
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Unit Tests Should Only Test Public Methods The short answer is that you shouldn't test private methods directly, but only their effects on the public methods that call them. Unit tests are clients of the object under test, much like the other classes in the code that are dependent on the object.
So whether you are using JUnit or SuiteRunner, you have the same four basic approaches to testing private methods: Don't test private methods. Give the methods package access. Use a nested test class.
Use the TestVisible annotation to allow test methods to access private or protected members of another class outside the test class. These members include methods, member variables, and inner classes. This annotation enables a more permissive access level for running tests only.
If we want to access Private Field and method using Reflection we just need to call setAccessible(true) on the field or method object which you want to access. Class. getDeclaredField(String fieldName) or Class. getDeclaredFields() can be used to get private fields.
Rather than the nasty #define hack you mention in the question, a cleaner mechanism is to make the test a friend of the class under test. This allows the test code (and just the test code) access to the privates, whilst protecting them from everything else.
However, it is preferable to test through the public interface. If your class X has a lot of code in the private member functions then it might be worth extracting a new class Y which is used by the implementation of class X. This new class Y can then be tested through its public interface, without exposing its use to the clients of class X.
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If you're using Google Test, you can use FRIEND_TEST to easily declare your test fixture as a friend to the class under test.
And you know, if testing private functions were unequivocally bad like some of the other answers were saying, then it probably wouldn't be built into Google Test.
You can read more about when testing private functions is good or bad in this answer.
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