fix(perf): make batches tests finish 30x faster (#3834)

In replay mode, inference is instantenous. We don't need to wait 15
seconds for the batch to be done. Fixing polling to do exp backoff makes
things work super fast.

tests/integration/batches/conftest.py

@@ -70,10 +70,15 @@ class BatchHelper:
     ):
         """Wait for a batch to reach a terminal status.
 
+        Uses exponential backoff polling strategy for efficient waiting:
+        - Starts with short intervals (0.1s) for fast batches (e.g., replay mode)
+        - Doubles interval each iteration up to a maximum
+        - Adapts automatically to both fast and slow batch processing
+
         Args:
             batch_id: The batch ID to monitor
             max_wait_time: Maximum time to wait in seconds (default: 60 seconds)
-            sleep_interval: Time to sleep between checks in seconds (default: 1/10th of max_wait_time, min 1s, max 15s)
+            sleep_interval: If provided, uses fixed interval instead of exponential backoff
             expected_statuses: Set of expected terminal statuses (default: {"completed"})
             timeout_action: Action on timeout - "fail" (pytest.fail) or "skip" (pytest.skip)
 
@@ -84,10 +89,6 @@ class BatchHelper:
             pytest.Failed: If batch reaches an unexpected status or timeout_action is "fail"
             pytest.Skipped: If timeout_action is "skip" on timeout or unexpected status
         """
-        if sleep_interval is None:
-            # Default to 1/10th of max_wait_time, with min 1s and max 15s
-            sleep_interval = max(1, min(15, max_wait_time // 10))
-
         if expected_statuses is None:
             expected_statuses = {"completed"}
 
@@ -95,6 +96,15 @@ class BatchHelper:
         unexpected_statuses = terminal_statuses - expected_statuses
 
         start_time = time.time()
+
+        # Use exponential backoff if no explicit sleep_interval provided
+        if sleep_interval is None:
+            current_interval = 0.1  # Start with 100ms
+            max_interval = 10.0  # Cap at 10 seconds
+        else:
+            current_interval = sleep_interval
+            max_interval = sleep_interval
+
         while time.time() - start_time < max_wait_time:
             current_batch = self.client.batches.retrieve(batch_id)
 
@@ -107,7 +117,11 @@ class BatchHelper:
                 else:
                     pytest.fail(error_msg)
 
-            time.sleep(sleep_interval)
+            time.sleep(current_interval)
+
+            # Exponential backoff: double the interval each time, up to max
+            if sleep_interval is None:
+                current_interval = min(current_interval * 2, max_interval)
 
         timeout_msg = f"Batch did not reach expected status {expected_statuses} within {max_wait_time} seconds"
         if timeout_action == "skip":