zig/doc/langref/test_coerce_optionals.zig

const std = @import("std");
const expect = std.testing.expect;

test "coerce to optionals" {
    const x: ?i32 = 1234;
    const y: ?i32 = null;

    try expect(x.? == 1234);
    try expect(y == null);
}

// test