Comment by 9rx

Not likely. The alternative was for them to modify SQLite without the test suite and no obvious indication of what they would need to do to try to fill in the gaps. Modifying SQLite with its full test suite would be the best choice, of course, but one that is apparently[1] not on the table for them. Since they have to reimagine the test suite either way, they believe they can do a better job if the tests are written alongside a new codebase.

And I expect they are right. Trying to test a codebase after the fact never goes well.

[1] With the kind of investment backing they have you'd think they'd be able to reach some kind of licensing deal, but who knows.