codex/codex-rs/utils/string/src/truncate/tests.rs

use super::split_string;
use super::truncate_middle_chars;
use super::truncate_middle_with_token_budget;
use pretty_assertions::assert_eq;

#[test]
fn split_string_works() {
    assert_eq!(split_string("hello world", 5, 5), (1, "hello", "world"));
    assert_eq!(split_string("abc", 0, 0), (3, "", ""));
}

#[test]
fn split_string_handles_empty_string() {
    assert_eq!(split_string("", 4, 4), (0, "", ""));
}

#[test]
fn split_string_only_keeps_prefix_when_tail_budget_is_zero() {
    assert_eq!(split_string("abcdef", 3, 0), (3, "abc", ""));
}

#[test]
fn split_string_only_keeps_suffix_when_prefix_budget_is_zero() {
    assert_eq!(split_string("abcdef", 0, 3), (3, "", "def"));
}

#[test]
fn split_string_handles_overlapping_budgets_without_removal() {
    assert_eq!(split_string("abcdef", 4, 4), (0, "abcd", "ef"));
}

#[test]
fn split_string_respects_utf8_boundaries() {
    assert_eq!(split_string("😀abc😀", 5, 5), (1, "😀a", "c😀"));

    assert_eq!(split_string("😀😀😀😀😀", 1, 1), (5, "", ""));
    assert_eq!(split_string("😀😀😀😀😀", 7, 7), (3, "😀", "😀"));
    assert_eq!(split_string("😀😀😀😀😀", 8, 8), (1, "😀😀", "😀😀"));
}

#[test]
fn truncate_with_token_budget_returns_original_when_under_limit() {
    let s = "short output";
    let limit = 100;
    let (out, original) = truncate_middle_with_token_budget(s, limit);
    assert_eq!(out, s);
    assert_eq!(original, None);
}

#[test]
fn truncate_with_token_budget_reports_truncation_at_zero_limit() {
    let s = "abcdef";
    let (out, original) = truncate_middle_with_token_budget(s, 0);
    assert_eq!(out, "…2 tokens truncated…");
    assert_eq!(original, Some(2));
}

#[test]
fn truncate_middle_tokens_handles_utf8_content() {
    let s = "😀😀😀😀😀😀😀😀😀😀\nsecond line with text\n";
    let (out, tokens) = truncate_middle_with_token_budget(s, 8);
    assert_eq!(out, "😀😀😀😀…8 tokens truncated… line with text\n");
    assert_eq!(tokens, Some(16));
}

#[test]
fn truncate_middle_bytes_handles_utf8_content() {
    let s = "😀😀😀😀😀😀😀😀😀😀\nsecond line with text\n";
    let out = truncate_middle_chars(s, 20);
    assert_eq!(out, "😀😀…21 chars truncated…with text\n");
}