On Windows you have this coming from Qt:
Qt Code: 
  1. #    define Q_DECL_EXPORT __declspec(dllexport)
  2. #    define Q_DECL_IMPORT __declspec(dllimport)
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as you can see, you ended up with the value of Q_DECL_IMPORT, which can only mean that your code:
Qt Code: 
  1. #ifdef BUILD_TEST_DLL
  2. #define TEST_IMPORT_EXPORT Q_DECL_EXPORT
  3. #else
  4. #define TEST_IMPORT_EXPORT Q_DECL_IMPORT
  5. #endif
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was preprocessed when BUILD_TEST_DLL was not defined.

If you add BUILD_TEST_DLL in your PRO file DEFINES, then you must rerun qmake to rewrite the Makefile or the value will not make it to the compiler.