Test the conversion of a string to a month. Note that this test will fail if the default
locale doesn't use English month names...devise a better test!
Test the conversion of a string to a weekday. Note that this test will fail if the
default locale doesn't use English weekday names...devise a better test!
Problem that the conversion of days to strings returns the right result. Actually, this
result depends on the Locale so this test needs to be modified.