Strange behavior in search-forward-regexp?

[Mathias Dahl <brakjoller@gmail.com>]

Take these "buffers":

Buffer 0:

---------- this line is not part of the buffer ----------
row0;test0
row1;test1
row2;test2
---------------------------------------------------------

Buffer 1:

---------- this line is not part of the buffer ----------

row0;test0
row1;test1
row2;test2
---------------------------------------------------------

Evaluate these functions:

(defun test1 ()
  (interactive)
  (save-excursion
    (goto-char (point-min))
    (if (search-forward-regexp "^[^;]+;.*test1" nil t)
        (message (match-string-no-properties 0)))))

(defun test2 ()
  (interactive)
  (save-excursion
    (goto-char (point-min))
    (if (search-forward-regexp "^.*test1" nil t)
        (message (match-string-no-properties 0)))))

In buffer 0, test1 and test2 willreturn the same result, "row1;test1",
but in buffer 1, test1 will return "\nrow1;test1" (\n is a newline)
and test2 "row1;test1".

Can someone explain this to me? Why would, in the case of test1, the
newline be included just because the line before is empty?