Add testing function and macro

include/utils.hpp

@@ -35,6 +35,8 @@
     #define DEBUG(msg)
 #endif
 
+#define ASSERT(expr) m_assert(expr, #expr, __FUNCTION__, __FILE__, __LINE__)
+
 /** Code stolen from https://github.com/anderkve/FYS3150
  *  Header: https://github.com/anderkve/FYS3150/blob/master/code_examples/compilation_linking/example_1/include/utils.hpp
  *  Source: https://github.com/anderkve/FYS3150/blob/master/code_examples/compilation_linking/example_1/src/utils.cpp
@@ -62,4 +64,6 @@ std::string scientific_format(const std::vector<double>& v,
                               int width=20, 
                               int prec=10);
 
+void m_assert(bool expr, const char* expr_str, const char* func, const char* file, int line);
+
 #endif