assert_all_are_classes
                        Is the input the name of a (formally defined)
                        class?
assert_is_S4            Is the input an S4 object?
assert_is_a_bool        Is the input logical?
assert_is_a_complex     Is the input complex?
assert_is_a_double      Is the input numeric?
assert_is_a_raw         Is the input raw?
assert_is_a_string      Is the input of type character?
assert_is_all_of        Does x belong to these classes?
assert_is_an_integer    Is the input an integer?
assert_is_array         Is the input an array or matrix?
assert_is_call          Is the input a language object?
assert_is_closure_function
                        Is the input a closure, builtin or special
                        function?
assert_is_data.frame    Is the input is a data.frame?
assert_is_data.table    Is the input a data.table?
assert_is_date          Is the input a date?
assert_is_environment   Is the input an environment?
assert_is_externalptr   Is the input is an external pointer?
assert_is_factor        Is the input a factor?
assert_is_formula       Is the input a formula?
assert_is_function      Is the input a function?
assert_is_inherited_from
                        Does the object inherit from some class?
assert_is_internal_function
                        Is the input an internal function?
assert_is_leaf          Is the input a (dendrogram) leaf?
assert_is_list          Is the input a list?
assert_is_mts           Is the input a time series?
assert_is_qr            Is the input a QR decomposition of a matrix?
assert_is_raster        Is the input a raster?
assert_is_relistable    Is the input relistable?
assert_is_s3_generic    Is the input an S3 generic or method?
assert_is_table         Is the input a table?
assert_is_tbl           Is the input a tbl?
assert_is_try_error     Is the input a condition?
