| assert_colnames | Assert that a data.frame contains specified column names |
| assert_coltypes | Assert that a data.frame's columns are certain types |
| assert_ids | Assert that a data.frame contains all unique combinations of specified ID variables, and doesn't contain duplicates within combinations |
| assert_nrows | Assert that a data.frame contains a specified number of rows |
| assert_values | Assert that a data.frame's columns are non-NA/infinite, or are greater, less than, equal/not-equal, or contain specified values. |
| check_files | Check for the existence of a vector of files, optionally repeated for a set amount of time. |
| import_files | Given a vector of filenames, append all files and return as one data.table using a user-defined function |