fix memory leak of test_chunked_read (#54)

Author: bicycle1885

src/testtools.jl

@@ -82,14 +82,13 @@ function test_chunked_read(Encoder, Decoder)
         data = mapfoldl(x->transcode(encoder, x), vcat, chunks, init=UInt8[])
         buffer = NoopStream(IOBuffer(data))
         ok = true
-        local stream
         for chunk in chunks
             stream = TranscodingStream(Decoder(), buffer, stop_on_end=true)
             ok &= hash(read(stream)) == hash(chunk)
             ok &= eof(stream)
+            close(stream)
         end
         Test.@test ok
-        close(stream)
     end
     finalize(encoder)
 end