SUMIF to sum only if test-value field is non-blank?

Hey Numbers experts, I'm looking for a way to conditionally sum the values in a column. In other words, if the corresponding field in my "test values" column is blank, I do not want to include the value from the same row in my "sum values" column. Is there a way to do this?

It seems that SUMIF is the perfect function, I just can't figure out a way to make it look for only non-blank fields. the test values, except for the blank fields, are all going to be unique values, so there is really nothing else to use as a test other than the presence or absence of data. Help?

Thanks in advance!