Agfdhyk

I have used googletest for my Android NDK project contain .c files. I have used a test class of the type .cpp to do the same. I want to use .c file instead. I get the following error when I try to use it :

Running main() from gtest_main.cc

[==========] Running 0 tests from 0 test cases.

[==========] 0 tests from 0 test cases ran. (1 ms total)

[  PASSED  ] 0 tests.

How can i solve this?

You cannot use a .c file to write a test class in googletest instead of a .cpp file.

A .c file should contain C language source code and a C/C++ compiler will assume that a .c file
is to be compiled as C.

A .cpp file should contain C++ language source code and a C/C++ compiler will assume that a .cpp file
is to be compiled as C++.

C and C++ are related but different programming languages. C is much older and simpler than C++.
There are no classes in the C language. C++ source code containing classes cannot be compiled as C.

Googletest is a unit-testing framework that is written in C++, not C, and it requires you to write
your test code in C++, using the framework classes. Your tests must coded in .cpp (and .h) files so that
the compiler will compile them as C++.

However, you can use googletest to unit-test C code. The C code will be in .c and .h files, but you
have to code your unit-tests, as usual, in .cpp and .h files. The C/C++ compiler knows that
the .c files are to be compiled as C and the .cpp files are to be compiled as C++.

There is a small complication that you must deal with when you want to #include "some_header.h"
in your C++ unit-test code, and some_header.h is one of the C-language header files:

The C++ compiler is going to process some_header.h, and it can process it correctly as long
as it knows that some_header.h is a C-language header file. To inform the C++ compiler that some_header.h
is a C header, you write this:

extern "C" {

#include "some_header.h"

}

If you don't put extern "C" { ... } around the #include for a C-language header then you will get undefined-symbol
errors at linktime.

I suggest that you experiment with a project containing the following three files:

return_one.h

// return_one.h

#ifndef RETURN_ONE_H

#define RETURN_ONE_H



// A C library :)



// A C function that always return 1.

extern int return_one(void);



#endif

return_one.c

// return_one.c

#include "return_one.h"



int return_one(void)

{

    return 1;

}

test_return_one.cpp

// test_return_one.cpp

#include "gtest/gtest.h"

extern "C" {

#include "return_one.h"

}



TEST(t_return_one, returns_1)

{

    EXPECT_EQ(1,return_one());  

}



int main(int argc, char **argv)

{

    ::testing::InitGoogleTest(&argc, argv);

    return RUN_ALL_TESTS();

}

Get this project to compile, link and run with googletest.

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