Updated test.cpp

Author: RadekM-92

homework/grayscale-image/test.cpp

@@ -4,6 +4,7 @@
 #include <vector>
 
 // TODO: include
+#include "compression.hpp"
 #include "gtest/gtest.h"
 
 void expectBitmap(const std::vector<std::pair<uint8_t, uint8_t>>& bitmap, size_t fraction) {