This test checks block-level space properties. These here are the examples 3 to 5 on the Wiki.

block 1: space-after conditional block 2: space-before conditional block 1: space-after retained block 2: space-before: conditional block 1: space-after retained block 2: space-before: conditional block 1: space-after retained block 2: space-before retained 3 3 3 3