Fix unified exec large output regex and remove python dependency

Author: codex-bot

codex-rs/core/tests/suite/unified_exec.rs

@@ -1621,11 +1621,8 @@ async fn unified_exec_formats_large_output_summary() -> Result<()> {
         ..
     } = builder.build(&server).await?;
 
-    let script = r#"python3 - <<'PY'
-import sys
-sys.stdout.write("token token \n" * 5000)
-PY
-"#;
+    // Avoid external deps (python) on CI runners; rely on coreutils/yes.
+    let script = r#"yes "token token " | head -n 5000"#;
 
     let call_id = "uexec-large-output";
     let args = serde_json::json!({
@@ -1678,7 +1675,8 @@ PY
     let large_output = outputs.get(call_id).expect("missing large output summary");
 
     let output_text = large_output.output.replace("\r\n", "\n");
-    let truncated_pattern = r"(?s)^Total output lines: \d+\n{2,}(token token \n){5,}.*…\d+ tokens truncated….*(token token \n){5,}$";
+    let output_text = output_text.trim_end();
+    let truncated_pattern = r"(?s)^Total output lines: \d+\n{2,}(token token ?\n){5,}.*…\d+ tokens truncated….*(token token ?\n?){5,}\s*$";
     assert_regex_match(truncated_pattern, &output_text);
 
     let original_tokens = large_output