assertThat(Ascii.truncate("foobar", 6, "…")).isEqualTo("foobar");
    assertThat(Ascii.truncate("foobar", 5, "…")).isEqualTo("foob…");
    assertThat(Ascii.truncate("foobar", 3, "")).isEqualTo("foo");
    assertThat(Ascii.truncate("", 5, "")).isEqualTo("");
    assertThat(Ascii.truncate("", 5, "...")).isEqualTo("");
    assertThat(Ascii.truncate("", 0, "")).isEqualTo("");
  }

    assertThat(Ascii.truncate("foobar", 6, "…")).isEqualTo("foobar");
    assertThat(Ascii.truncate("foobar", 5, "…")).isEqualTo("foob…");
    assertThat(Ascii.truncate("foobar", 3, "")).isEqualTo("foo");
    assertThat(Ascii.truncate("", 5, "")).isEqualTo("");
    assertThat(Ascii.truncate("", 5, "...")).isEqualTo("");
    assertThat(Ascii.truncate("", 0, "")).isEqualTo("");
  }

            // Fallback: truncate the newest message to fit
            final LlmMessage newest = history.get(history.size() - 1);
            final String truncated = newest.getContent().substring(0, Math.min(budgetChars, newest.getContent().length()));
            request.addMessage(new LlmMessage(newest.getRole(), truncated));
            if (logger.isDebugEnabled()) {

        // Empty titles => suffix is empty => falls back to truncated
        assertEquals("Some content here that is quite long enough to be truncated.", result);
    }

    // ========== additional truncated tests ==========

    @Test
    public void test_truncated_nullContent() {
        final ChatMessage msg = ChatMessage.assistantMessage(null);

        assertNotNull(details);
        // Max 50 events displayed, message truncated to 200 chars
        assertTrue(details.contains("Total: 100 event(s) (showing 50)"));
        assertTrue(details.contains("... and 50 more"));
        // Long messages should be truncated with "..."
        assertTrue(details.contains("..."));
    }

    @Test

          "type":       "stop",
          "stopwords_path": "${fess.dictionary.path}vi/stopwords.txt"
        },
        "truncate10_filter" : {
          "type" : "truncate",
          "length" : 10
        },
        "truncate20_filter" : {
          "type" : "truncate",
          "length" : 20
        },
        "alphanum_word_filter" : {
          "type" : "alphanum_word",
          "max_token_length" : 20
        },

            sb.append("a");
        }
        String longScript = sb.toString();

        String result = activityHelper.normalizeScript(longScript);

        // Should be truncated to 100 characters (97 + "...")
        assertEquals(100, result.length());
        assertTrue(result.endsWith("..."));
    }

    @Test
    public void test_normalizeScript_exactlyMaxLength() {

     *
     * @param msg the assistant chat message
     * @param mode the content mode (full, smart_summary, source_titles, source_titles_and_urls, truncated, none)
     * @param assistantMaxChars the maximum characters for truncated mode
     * @param summaryMaxChars the maximum characters for summary modes
     * @return the content string for history, or null if the message should be excluded
     */

     * @param maxDisplayEvents the maximum number of events to display
     * @param maxMessageLength the maximum length of each log message
     * @return the formatted details string with summary header and truncated entries
     */
    protected String formatDetails(final List<LogNotificationEvent> events, final int maxDetailsLength, final int maxDisplayEvents,
            final int maxMessageLength) {

            if (s == null) return "null";
            String t = s.replace("\n", "\\n");
            if (t.length() > 500) {
                return t.substring(0, 500) + "...(truncated)";
            }
            return t;
        }
    }

    private static ExecResult exec(String[] command) throws IOException, InterruptedException, ExecutionException {