def METHOD_NAME(folder):
    """
    Performs the actual checking of convenience header for specific folder.
    Checks that
    1) The header even exists
    2) That all includes in the header are sorted
    3) That there are no duplicated includes
    4) That all includes that should be in the header are actually present in the header
    5) That there are no superfluous includes that should not be in the header
    """
    global errors_found
    path = normalized_path(folder.path)
    assert path.startswith(source_path), '{} does not start with {}'.format(path, source_path)
    stripped_path = path[len(source_path) + 1:]
    path_pieces = stripped_path.split('/')
    if path == source_path:
        header_name = 'catch_all.hpp'
    else:
        header_name = 'catch_{}_all.hpp'.format('_'.join(path_pieces))
    # 1) Does it exist?
    full_path = path + '/' + header_name
    if not os.path.isfile(full_path):
        errors_found = True
        print('Missing convenience header: {}'.format(full_path))
        return
    file_incs = includes_from_file(path + '/' + header_name)
    # 2) Are the includes are sorted?
    if sorted(file_incs) != file_incs:
        errors_found = True
        print("'{}': Includes are not in sorted order!".format(header_name))
    # 3) Are there no duplicates?
    duplicated = get_duplicates(file_incs)
    for duplicate in duplicated:
        errors_found = True
        print("'{}': Duplicated include: '{}'".format(header_name, duplicate))
    target_includes = normalize_includes(collated_includes(path))
    # Avoid requiring the convenience header to include itself
    target_includes = [x for x in target_includes if header_name not in x]
    # 4) Are all required headers present?
    file_incs_set = set(file_incs)
    for include in target_includes:
        if (include not in file_incs_set and
            include != 'catch2/internal/catch_windows_h_proxy.hpp'):
            errors_found = True
            print("'{}': missing include '{}'".format(header_name, include))
    # 5) Are there any superfluous headers?
    desired_set = set(target_includes)
    for include in file_incs:
        if include not in desired_set:
            errors_found = True
            print("'{}': superfluous include '{}'".format(header_name, include))