Setup unit test framework without the need to include source files

[dschlaep]

Currently, unit tests only compile if the test/*.cc files #include "SW_*.c" the relevant SOILWAT2 source files.

This is obviously bad. We need to set up our unit test framework without the need to include source files

[dschlaep]

g++ -isystem googletest/googletest/include -pthread libgtest.a libSOILWAT2.a test/*.cc
-o sw_test
Undefined symbols for architecture x86_64:
"RandBeta(float, float)", referenced from:
(anonymous namespace)::BetaGeneratorTest_ZeroToOneOutput_Test::TestBody() in test_rands-6fe717.o
(anonymous namespace)::BetaGeneratorDeathTest_Errors_Test::TestBody() in test_rands-6fe717.o
ld: symbol(s) not found for architecture x86_64

I don't understand why I get undefined symbols for architecture x86_64 errors...

Maybe the problem is that I compile libSOILWAT2.a with gcc and here I have to use g++ to compile with the googletest because it is c++?

• However, if I don't include libSOILWAT2.a but instead the c-source files $(sources) directly (e.g., following https://stackoverflow.com/questions/41453253/googletest-cmake-undefined-symbols-for-architecture-x86-64) -- each prefixed with -x c --, then I get exactly the same error Undefined symbols for architecture x86_64.
• If I don't include the c-source files $(sources) as c-language files, but instead as c++-files, then I get tons of additional errors such as error: cannot initialize return object of type 'OutPeriod' with an lvalue of type 'IntUS' (aka 'unsigned short') etc.

[dschlaep]

When I include the SOILWAT2 source files as library to link to my unit test executable, it fails with undefined symbols ...:

c++ -Wall -Wextra -std=gnu++11 -L. -isystem googletest/googletest/include -pthread test/*.cc -o sw_test -lgtest -lSOILWAT2 -lm			

When I list the SOILWAT2 source files directly in the compile command, it works:

c++ -Wall -Wextra -std=gnu++11 -L. -isystem googletest/googletest/include -pthread rands.c generic.c mymemory.c filefuncs.c test/*.cc -o sw_test -lgtest

It produces warnings clang: warning: treating 'c' input as 'c++' when in C++ mode, this behavior is deprecated. When I include the -x c flag to indicate c-code files, then I get the same undefined symbols error. It seems that the CXX linker can only successfully find symbols when they are compiled as c++; it fails when they are interpreted as c code (with -x c) or when they are linked as library (that was compiled with a c-compiler).

So I should compile a c++ version of libSOILWAT2. The problem is that we have a good portion of ancient, weird code that is not compatible with c++, e.g., all they typedef enum {...} Months; and then Months m; for (m = Jan; m <= Dec; m++) constructs.