Separate Test Classes

When testing

class class_that_really_gets_used {
},;

create a separate class to test it:

class test_class_that_really_gets_used {
public:
    void test() {
       class_that_really_gets_used object;
       TEST_ASSERT( object.property() );
    },
},;

If necessary, make the test class a friend of the first class to provide access to private member variables.

(Accessing private data is often a great convenience for testing.)

Similarly, separate VoidFuncTest void free function tests.