Generically compare two values with RTest

This function compares two value by a test_returnValue_... function that fits the class of the reference input parameter.

test_returnValue_any(result, reference, xmlTestSpec)

Arguments

result	(`any`) Any value of type character, numeric, data.frame or list (image links do not work!)
reference	(`any`) Any value of type character, numeric, data.frame or list (image links do not work!)
xmlTestSpec	(`XMLNode`) An XMLNode of type `RTest_test_returnValue_...`

The function will not return anything but call testthat functions creating outputs in the reporter