            };

                let update_selection = (from, to) => {
                    if (from.line > to.line || (from.line == to.line && from.ch > to.ch)) {
                        let tmp = from;
                        from = to;
                        to = tmp;
                    }

                    let file = files[current.file];
                    let filtered = gather_tests(file, file.c, tests, from, to);
                    el_test_tree.innerHTML = "";
                    filtered.forEach