First black boxes or white boxes

Question

Which test cases should be written first black boxes or white boxes?

Answer 1

Generally black box test cases are preferred to written first and then white box test cases. If we want to write black box test cases first then we have to prepare the requirement document and, design plan. All these documents are simply available at the preliminary stage of the project. For black box testing we only need only examine from the functional point of view which is simply accessible from a plain requirement document.
Black box test cases do not need system understanding where as white box testing needs more structural understanding. White box need more architecture clearness which is not accessible at the start of the project, hence white box test cases could not be started in the early stage of the project. Therefore usually black box test cases are written first and the white box test cases are written.