Rename folder of core library

core-writer/test/test_main.cpp

@@ -0,0 +1,12 @@
+#include "gtest/gtest.h"
+#include "test_ZmqReceiver.cpp"
+#include "test_H5Writer.cpp"
+#include "test_MetadataBuffer.cpp"
+#include "test_BufferedWriter.cpp"
+
+using namespace std;
+
+int main(int argc, char **argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}