fix readuntil when stream is empty (#74)

Author: bicycle1885

src/stream.jl

@@ -337,6 +337,10 @@ function Base.readuntil(stream::TranscodingStream, delim::UInt8; keep::Bool=fals
             break
         end
     end
+    if !@isdefined(ret)
+        # special case: stream is empty
+        ret = UInt8[]
+    end
     return ret
 end
 

test/codecnoop.jl

@@ -260,6 +260,11 @@
     close(stream)
     @test eof(stream)  # close
 
+    stream = NoopStream(IOBuffer(""))
+    data = readuntil(stream, 0x00)
+    @test data isa Vector{UInt8}
+    @test isempty(data)
+
     @test_throws ArgumentError NoopStream(IOBuffer(), bufsize=0)
     @test_throws ArgumentError NoopStream(let s = IOBuffer(); close(s); s; end)
     @test_throws ArgumentError TranscodingStream(Noop(), IOBuffer(), bufsize=0)