ApprovalTests.cpp | Native ApprovalTests for C on Linux , Mac and Windows | Testing library

I'm writing approval tests using the excellent ApprovalTests.cpp library. This library automates generation of "snapshots" of results from a function. Snapshots are generated serializing results of type T to a file using the ostream& operator<< (T val).

This operator has always been the C++ convention for formatting some value to a textual representation. While primitive types support this operator and you can write your own implementation for custom types, there isn't a standard implementation for STL containers like std::vector.

You can implement your own, even using other libraries like fmt or pprint. Here are some example with similar outputs. I use the generic type STREAM as parameter instead of the concrete type ostream as recommended by ApprovalTests.cpp but the idea doesn't change.