zig/test/standalone/issue_13030/build.zig

const std = @import("std");
const builtin = @import("builtin");
const CrossTarget = std.zig.CrossTarget;

pub fn build(b: *std.Build) void {
    const test_step = b.step("test", "Test it");
    b.default_step = test_step;

    add(b, test_step, .Debug);
    add(b, test_step, .ReleaseFast);
    add(b, test_step, .ReleaseSmall);
    add(b, test_step, .ReleaseSafe);
}

fn add(b: *std.Build, test_step: *std.Build.Step, optimize: std.builtin.OptimizeMode) void {
    const obj = b.addObject(.{
        .name = "main",
        .root_source_file = .{ .path = "main.zig" },
        .optimize = optimize,
        .target = .{},
    });

    test_step.dependOn(&obj.step);
}