What if there's a problem in your test data and you end up loading ten times the number of records that you intended to run? How will you catch that?

I should be clear here, I'm not testing a module...I'm testing that a database conversion went as expected. In college, I had a warehouse job. Our mantra there was "If it came in by count, count it. If it came in by weight, weigh it". That's exactly what I'm doing here. I do counts before and after as a first level check. One of the tables is non-normalized in that it has the same 3 columns repeated over and over to reperesent different things (think a family; the columns are dad's hair color, occupation, and age, mom's hair color, occupation, and age, etc). There are a different number of sets depending on the database. For each of these sets of columns, I want to check that it got into the normalized structure correctly. Once the counts are verified, I "weigh" it. That is to say that I make sure that the quality of the data before and is the same.