Tests for setting the '[,'] marks when joining lines.

STARTTEST
:so small.vim
:/^\t\t/
0gqj:
:let a=string(getpos("'[")).'/'.string(getpos("']"))
:/^This line/;'}-join
:let b=string(getpos("'[")).'/'.string(getpos("']"))
:$put ='First test: Start/End '.string(a)
:$put ='Second test: Start/End '.string(b)
:/^\t\t/,$wq! test.out
ENDTEST


		O sodales, ludite, vos qui
attamen consulite per voster honur. Tua pulchra facies me fay planszer milies

This line.
Should be joined with the next line
and with this line

Results: