   describe 'in stream mode', ->
 
     createRunner = (rebuildOpts, sourceChunks, expected) ->
+      sourceChunks = clone sourceChunks
       (done) ->
         contentStream = new PassThrough
 

                      attrs.class?
        attrs.class = ("module-#{cls}" for cls in attrs.class.split /\s+/g).join ' '
        "<#{name}#{createAttrStr attrs}>"
    , clone(htmlChunks)
    , """
    <!DOCTYPE html>
    <html>

                      attrs.class?
        classStr = (".#{cls}" for cls in attrs.class.split /s+/g).join ''
        "<!-- /#{classStr} --></#{name}>"
    , htmlChunks
    , """
    <!DOCTYPE html>
    <html>
