Remove single line breaks, keep “empty” lines

Question

Say I have text like the following text selected with the cursor:

This is a test. 
This 
is a test.

This is a test. 
This is a 
test.

I wo

Answer 1

I believe this will work:

text=
(
This is a test. 
This 
is a test.

This is a test. 
This is a 
test.
)
MsgBox %    RegExReplace(text,"\S\K\v(?=\S)",A_Space)