assert                  Explicitly state that we expect no errors to
                        occur.
create_file_structure   Create a file structure for tests.
expect_is_file          Return an error if a string represents an
                        existent file.
is.directory            Check whether a path is a directory.
stub<-                  Stub the environment of a closure.
testthatsomemore        This package is intended as a companion to the
                        testthat package with additional support for:
touch                   Touch a file.
