testRoundtripWtf8

fn testRoundtripWtf8(wtf8: []const u8) !void {
    // Buffer
    {
        var wtf16_buf: [32]u16 = undefined;
        const wtf16_len = try wtf8ToWtf16Le(&wtf16_buf, wtf8);
        try testing.expectEqual(wtf16_len, calcWtf16LeLen(wtf8));
        const wtf16 = wtf16_buf[0..wtf16_len];

        var roundtripped_buf: [32]u8 = undefined;
        const roundtripped_len = wtf16LeToWtf8(&roundtripped_buf, wtf16);
        const roundtripped = roundtripped_buf[0..roundtripped_len];

        try testing.expectEqualSlices(u8, wtf8, roundtripped);
    }
    // Alloc
    {
        const wtf16 = try wtf8ToWtf16LeAlloc(testing.allocator, wtf8);
        defer testing.allocator.free(wtf16);

        const roundtripped = try wtf16LeToWtf8Alloc(testing.allocator, wtf16);
        defer testing.allocator.free(roundtripped);

        try testing.expectEqualSlices(u8, wtf8, roundtripped);
    }
    // AllocZ
    {
        const wtf16 = try wtf8ToWtf16LeAllocZ(testing.allocator, wtf8);
        defer testing.allocator.free(wtf16);

        const roundtripped = try wtf16LeToWtf8AllocZ(testing.allocator, wtf16);
        defer testing.allocator.free(roundtripped);

        try testing.expectEqualSlices(u8, wtf8, roundtripped);
    }
}