Add compression exit function clause (#4)

Author: owenbob

lib/z_stream/lz4.ex

@@ -60,6 +60,10 @@ defmodule ZStream.LZ4 do
     {:erlang.iolist_to_iovec(finish), ref}
   end
 
+  defp do_compress_exit({:start, ref}) do
+    :lz4f.compress_end(ref)
+  end
+
   defp do_compress_exit(ref) do
     :lz4f.compress_end(ref)
   end

test/z_stream/lz4_test.exs

@@ -30,4 +30,21 @@ defmodule ZStream.LZ4Test do
 
     assert Enum.into(stream, "") == ""
   end
+
+  test "compress empty stream" do
+    empty_data = []
+    stream = ZStream.compress(empty_data, LZ4)
+    result = Enum.into(stream, [])
+
+    assert [_ | _] = result
+  end
+
+  test "decompress empty stream" do
+    empty_data = []
+    compressed = ZStream.compress(empty_data, LZ4)
+    compressed_bytes = Enum.into(compressed, [])
+    decompressed = ZStream.decompress(compressed_bytes, LZ4)
+
+    assert Enum.into(decompressed, "") == ""
+  end
 end