assert_that             Scoped Assertions
collapse                Collapse character Vectors
comma_list              Construct a comma separated list
condition               Raise a mutable and classed condition.
dot-underscore          Format and Translate Strings
find_scope              Find the default scope of a call.
infix-concatenation     Infix string concatenation.
not-in                  Not in infix operator
skip_scope              Exclude a function from find_scope
suppress                Selectively suppress warnings and messages
