diff --git a/make.sh b/make.sh
index dcf8923..4ee764c 100755
--- a/make.sh
+++ b/make.sh
@@ -1,2 +1,2 @@
 #!/bin/bash
-clear; clear; g++ -x c -fmax-errors=5 -pedantic -Wall -Wextra -o test raycastlib.c 2>&1 >/dev/null && ./test
+clear; clear; g++ -x c -fmax-errors=5 -pedantic -Wall -Wextra -o test test.c 2>&1 >/dev/null && ./test
diff --git a/raycastlib.c b/raycastlib.h
similarity index 76%
rename from raycastlib.c
rename to raycastlib.h
index e72cf98..6d70ffd 100644
--- a/raycastlib.c
+++ b/raycastlib.h
@@ -1,5 +1,7 @@
+#ifndef RAYCASTLIB_H
+#define RAYCASTLIB_H
+
 #include <stdint.h>
-#include <stdio.h>
 
 /**
   author: Miloslav "drummyfish" Ciz
@@ -66,16 +68,6 @@ void castRayMultiHit(Ray ray, int16_t (*arrayFunc)(int16_t, int16_t),
 //=============================================================================
 // privates
 
-#define logVector2D(v)  printf("[%d,%d]\n",v.x,v.y)
-#define logRay(r)       printf("ray:\n");\
-                        printf("  start: "); logVector2D(r.start);\
-                        printf("  dir: "); logVector2D(r.direction);
-#define logHitResult(h) printf("hit:\n");\
-                        printf("  sqaure: "); logVector2D(h.square);\
-                        printf("  pos: "); logVector2D(h.position);\
-                        printf("  dist: %d", h.distance);\
-                        printf("  texcoord: %d", h.textureCoord);
-
 uint16_t sqrtInt(uint32_t value)
 {
   uint32_t result = 0;
@@ -250,58 +242,4 @@ HitResult castRay(Ray ray, int16_t (*arrayFunc)(int16_t, int16_t),
   return result;
 }
 
-int16_t testArrayFunc(int16_t x, int16_t y)
-{
-  return (x < 0 || y < 0 || x > 9 || y > 9) ? 1 : 0;
-}
-
-/**
-  Simple automatic test function.
-*/
-
-int testSingleRay(Unit startX, Unit startY, Unit dirX, Unit dirY,
-  int16_t expectSquareX, int16_t expectSquareY, int16_t expectPointX,
-  int16_t expectPointY, int16_t tolerateError)
-{
-  Ray r;
-
-  r.start.x     = startX;
-  r.start.y     = startY;
-  r.direction.x = dirX;
-  r.direction.y = dirY;
-
-  HitResult h = castRay(r,testArrayFunc,20);
-  
-  return
-      h.square.x   == expectSquareX &&
-      h.square.y   == expectSquareY &&
-      h.position.x <= expectPointX + tolerateError &&
-      h.position.x >= expectPointX - tolerateError &&
-      h.position.y <= expectPointY + tolerateError &&
-      h.position.y >= expectPointY - tolerateError;
-}
-
-int test()
-{
-  if (!testSingleRay(
-    3 * UNITS_PER_SQUARE + UNITS_PER_SQUARE / 2,
-    4 * UNITS_PER_SQUARE + UNITS_PER_SQUARE / 2,
-    100, 50,
-    10, 7,
-    10240, 7936,
-    16))
-    return 0; 
-
-  return 1;
-}
-
-int main()
-{
-  printf("%d\n",test()); 
-
-  return 0;
-}
-
-#undef logVector2D
-#undef logRay
-#undef logHitResult
+#endif
diff --git a/test.c b/test.c
new file mode 100644
index 0000000..323459e
--- /dev/null
+++ b/test.c
@@ -0,0 +1,87 @@
+#include "raycastlib.h"
+#include <stdio.h>
+
+void logVector2D(Vector2D v)
+{
+  printf("[%d,%d]\n",v.x,v.y);
+}
+
+void logRay(Ray r)
+{
+  printf("ray:\n");
+  printf("  start: ");
+  logVector2D(r.start);
+  printf("  dir: ");
+  logVector2D(r.direction);
+}
+
+void logHitResult(HitResult h)
+{
+  printf("hit:\n");\
+  printf("  sqaure: ");
+  logVector2D(h.square);
+  printf("  pos: ");
+  logVector2D(h.position);
+  printf("  dist: %d", h.distance);
+  printf("  texcoord: %d", h.textureCoord);
+}
+
+int16_t testArrayFunc(int16_t x, int16_t y)
+{
+  return (x < 0 || y < 0 || x > 9 || y > 9) ? 1 : 0;
+}
+
+/**
+  Simple automatic test function.
+*/
+
+int testSingleRay(Unit startX, Unit startY, Unit dirX, Unit dirY,
+  int16_t expectSquareX, int16_t expectSquareY, int16_t expectPointX,
+  int16_t expectPointY, int16_t tolerateError)
+{
+  Ray r;
+
+  r.start.x     = startX;
+  r.start.y     = startY;
+  r.direction.x = dirX;
+  r.direction.y = dirY;
+
+  printf("- casting ray:\n");
+  logRay(r);
+
+  HitResult h = castRay(r,testArrayFunc,20);
+  
+  printf("- result:\n");
+  logHitResult(h);
+
+  int result = 
+    h.square.x   == expectSquareX &&
+    h.square.y   == expectSquareY &&
+    h.position.x <= expectPointX + tolerateError &&
+    h.position.x >= expectPointX - tolerateError &&
+    h.position.y <= expectPointY + tolerateError &&
+    h.position.y >= expectPointY - tolerateError;
+
+  if (result)
+    printf("\nOK\n");
+  else
+    printf("\nFAIL\n");
+
+  return result;
+}
+
+int main()
+{
+  printf("Testing raycastlib.\n"); 
+
+  if (!testSingleRay(
+    3 * UNITS_PER_SQUARE + UNITS_PER_SQUARE / 2,
+    4 * UNITS_PER_SQUARE + UNITS_PER_SQUARE / 2,
+    100, 50,
+    10, 7,
+    10240, 7936,
+    16))
+    return 1; 
+
+  return 0;
+}