Fix flaky terminal kill test (#52370)

Mikayla Maki created 2 weeks ago

## Context

This test was bugging me, so I had claude take a look at it.


## Self-Review Checklist

<!-- Check before requesting review: -->
- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

Release Notes:

- N/A

Change summary

crates/acp_thread/src/acp_thread.rs | 24 +++++++++++++++++++++---
1 file changed, 21 insertions(+), 3 deletions(-)

Detailed changes

crates/acp_thread/src/acp_thread.rs

@@ -3177,9 +3177,27 @@ mod tests {
             );
         });
 
-        // Wait for the printf command to execute and produce output
-        // Use real time since parking is enabled
-        cx.executor().timer(Duration::from_millis(500)).await;
+        // Poll until the printf command produces output, rather than using a
+        // fixed sleep which is flaky on loaded machines.
+        let deadline = std::time::Instant::now() + Duration::from_secs(10);
+        loop {
+            let has_output = thread.read_with(cx, |thread, cx| {
+                let term = thread
+                    .terminals
+                    .get(&terminal_id)
+                    .expect("terminal not found");
+                let content = term.read(cx).inner().read(cx).get_content();
+                content.contains("output_before_kill")
+            });
+            if has_output {
+                break;
+            }
+            assert!(
+                std::time::Instant::now() < deadline,
+                "Timed out waiting for printf output to appear in terminal",
+            );
+            cx.executor().timer(Duration::from_millis(50)).await;
+        }
 
         // Get the acp_thread Terminal and kill it
         let wait_for_exit = thread.update(cx, |thread, cx| {