% use the name of the folder you want to check:
folder = './';
% get info about the files in that folder whose name starts with 'test' and
% whose extension is .mat:
files = dir(fullfile(folder,'test*.mat'));
% see the files' names:
{files.name}
% and/or, see if there is more than one such file:
numel(files) > 1
% etc.
