You should have two users, for example, user1 and user2.
Steps to reproduce:
1. Login as user1 and send private message(pm further) to user2. Let the message body will be "message".
2. Relogin as user2, go to pm, choose last pm from user1 and push on "Quote" button.
Expected result:
message body is >>message
Actual result:
message body is <message
3. Start a new line and write "answer". Send message. Relogin as user1, go to pm, choose last pm from user2.
Expected result:
>>message
answer
Actual result:
<message answer
4. Push on "Quote" button.
Expected result:
>>message
>>answer
Actual result:
<<message answer
----------------------------------------
Quote example

each new line beginning with ">":
>>>> some text1
>>> reply
>> reply
> reply
current message

need to add the space between ">" and line if there is not ">" or space in the start of the line:
input — "line"
output — "> line"
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Test case
http://jtalks.org/display/jcommune/TC-JC-16+Creating+and+sending+new+personal+message