Test process method works correctlySource:
Test data can be processed correctly using the process method.
process is invoked to generate processed data which is then checked to ensure
it is a data.frame, which is not empty, has at least 2 columns and calls
expect_processed_columns to check each column types.
The R6Class object to perform checks on. Must be a
Logical. Run tests with all settings (TRUE) or with those defined in the current class instance (FALSE). Defaults to FALSE.