are_equal               Are two objects equal?
assert_that             Assert that certain conditions are true.
assertions-file         Useful test related to files
has_args                Check a function has specified arguments
has_attr                Has attribute or name?
is.error                Missing is functions.
is.scalar               Assert input is a scalar.
noNA                    Does object contain any missing values?
not_empty               Check an object doesn't have any empty
                        dimensions
on_failure              Custom failure messages for assertions.
validate_that           Validate that certain conditions are true.