Suppose there is a function  get-data which returns a map of information about the id of the user passed in.now this function uses 3 functions source-a, source-b and source-c to get three different kinds of maps.now we combine all these maps into one map and return from get-data.when I test get-data, should I test for existence of data for keys ?Does it makes sense for this function to fail unit tests if one of  source-a, source-b and source-c fail?If thats function job is to combine data,and its doing it, it should be enough right ?
How should I test the functionality of a function that uses other functions in it?
unit testing