By far the slowest test is now create_accounts_with_non_zero_anchor_block which doesn't do any proving. It is slow because it creates $2^{16}$ blocks with the MockChain to test an account ID creation with something other than the genesis block as the anchor. If we could speed up the creation of fake blocks in the mock chain that would help here. I guess the slow part comes from all the hashing in the MMR operations, not sure if we can cheat here somehow.

Originally posted by @PhilippGackstatter in #1230 (comment)

So the main question is, can we somehow speed up block creation in the MockChain. For example, when we are at block 0 and need block 1000 for the test, can we somehow efficiently create blocks 1..=1000?