function copy(from, to) {
fileWriter(to, fileReader(from));
}
function testCopy() {
// Overskriv reader/writer
files = {};
function fileReader(filename) {
return files[filename];
}
function fileWriter(filename, content) {
files[filename] = content;
}
copy('a', 'b')
assert(files['a'] === files['b']);
}