diff --git a/src/test_png.c b/src/test_png.c
new file mode 100644
index 0000000..94f386b
--- /dev/null
+++ b/src/test_png.c
@@ -0,0 +1,23 @@
+#include <stdio.h>
+#include "render.h"
+#include "write_png.h"
+
+int angle_to_pixel_white(double *angle, double *rgb) {
+  rgb[0] = 1.0;
+  rgb[1] = 1.0;
+  rgb[2] = 1.0;
+  return 0;
+}
+
+int main(){
+  int W = 1;
+  int H = 1;
+  double w = 1;
+  System system = {W, H, w, angle_to_pixel_white};
+
+  double buffer[W*H][3];
+
+  render(&system, buffer, 10000, 1.0/256, 1e-1);
+  write_png("test_white.png", buffer, W, H);
+  return 0;
+}