Using zig code to unit test legacy C/C++ code

Help
1

I just saw this
Build mix cpp and zig code - Help - Ziggit
Can I use zig to build my C++ code and unit test it from zig as long as the include files, in the C++ file, only is a simple C header file?

2

Yes, you can.

Yes, you can call functions using C ABI (callable by C using extern “C” ).

3

I’ve used catchorg/Catch2 to test C/C++ codes.

Following is a Zig side code:

const std = @import("std");

extern fn run_catch2_test(test_report_path: [*c]const u8) callconv(.C) c_int;

const TEST_OUTPUT: [:0]const u8 = "test_result.txt";

pub fn run_catch2(allocator: std.mem.Allocator) !c_int {
    const err = run_catch2_test(TEST_OUTPUT);
    if (err > 0) {
        const file = try std.fs.cwd().openFile(TEST_OUTPUT, .{});
        defer file.close();

        const meta = try file.metadata();
        const data = try file.readToEndAlloc(allocator, meta.size());
        defer allocator.free(data);

        std.debug.print("Catch2 output:\n{s}\n", .{data}); 
    }

    return err;
}

Following is a C code:

#include <catch2/catch_session.hpp>
#include <iostream>
#include <fstream>

extern "C" {

auto run_catch2_test(const char *redirect_path) -> int {
    std::ofstream out(redirect_path);
    std::streambuf* coutbuf = std::cout.rdbuf(); 
    std::cout.rdbuf(out.rdbuf()); 

    int argc = 1;
    const char* argv[] = { "your_program_name" };

    Catch::Session session;

    session.applyCommandLine(argc, argv);

    auto result = session.run();

    std::cout.rdbuf(coutbuf); 
    return result;
}

}

EDIT: I’ve dump to textfile in C-side to print the textfile in Zig-side because Zig locks stdout