How to do TDD in zig?

[zenith tide]

Hi, I want write my zig code and debug it while I write it. One of the things this cause is I do not want variables to be optimized away while I write them. Is there a way to ensure this with the build?

My file looks something like this.

const std = @import("std");

fn readEntireFile(filename: []const u8) !void {
    const file = try std.fs.cwd().openFile(filename, .{});
    const stat = try file.stat();
    _ = stat; // I include a breakpoint here in VScode to debug.
}

test {
    _ = try readEntireFile("data_1_flex.json");
}

The thing stat gets optimized away. How can I prevent this? Right now the only thing that worked was adding.

std.debug.print("{d}", .{stat.mode});

But I'd prefer not to.

[zealous oak]

what happens if you do _ = &stat;?

although part of the problem may be that there are no lines of code that produce runtime code after const stat

[final dagger]

there's also std.mem.doNotOptimizeAway

[zenith tide]

std.mem.doNotOptimizeAway didn't work :/

Huh, interesting. The _ = &stat; worked. Why?

[zealous oak]

Unused variables don't show up in the debugger, _ = &stat; references the address of the variable forcing it to be stored on the stack and be easily accessible by the debugger