diff --git a/nimPNG.nim b/nimPNG.nim
index 1c47ded..5750d1f 100644
--- a/nimPNG.nim
+++ b/nimPNG.nim
@@ -25,9 +25,9 @@
 # part of nimPDF sister projects
 #-------------------------------------
 
-import streams, endians, tables, hashes, math, nimz
+import streams, endians, tables, hashes, math
 
-import private.buffer
+import private.buffer, private.nimz
 
 const
   NIM_PNG_VERSION = "0.1.8"
@@ -769,7 +769,7 @@ proc createChunk(png: PNG, chunkType: PNGChunkType, data: string, crc: uint32):
 
   if result != nil:
     result.initChunk(chunkType, data, crc)
-    
+
 proc makePNGDecoder*(): PNGDecoder =
   var s: PNGDecoder
   new(s)
diff --git a/nimz.nim b/private/nimz.nim
similarity index 100%
rename from nimz.nim
rename to private/nimz.nim
diff --git a/testCodec.nim b/tester/testCodec.nim
similarity index 99%
rename from testCodec.nim
rename to tester/testCodec.nim
index 8283071..7be1226 100644
--- a/testCodec.nim
+++ b/tester/testCodec.nim
@@ -1014,8 +1014,8 @@ proc testAutoColorModels() =
 
 proc testFilter() =
   echo "test Filter"
-  let input = "tester" & DirSep & "tfilter.png"
-  let temp = "tester" & DirSep & "temp.png"
+  let input = "tfilter.png"
+  let temp = "temp.png"
   let png = loadPNG32(input)
   discard savePNG32(temp, png.data, png.width, png.height)
   let png2 = loadPNG32(temp)
diff --git a/testSuite.nim b/tester/testSuite.nim
similarity index 98%
rename from testSuite.nim
rename to tester/testSuite.nim
index 4a9c4ee..db49af5 100644
--- a/testSuite.nim
+++ b/tester/testSuite.nim
@@ -85,4 +85,4 @@ proc convert(dir: string) =
       let data2 = readFile(bmpName)
       assert data1 == data2
 
-convert("suite")
+convert(".." & DirSep & "suite")