fix: restore original retry_on_transient_error signature and linear backoff

Author: aliev

tests/base.py

@@ -69,17 +69,8 @@ def _is_transient_error(exc: Exception) -> bool:
     return False
 
 
-def retry_on_transient_error(max_retries=3, base_delay=2.0, max_delay=30.0):
-    """Retry a flaky integration test with exponential backoff.
-
-    Apply to tests that hit the Stream API and can fail due to rate limits,
-    resource limits, or transient infrastructure errors.
-
-    Args:
-        max_retries: Maximum number of retry attempts.
-        base_delay: Initial delay in seconds (doubles each attempt).
-        max_delay: Cap on the delay between retries.
-    """
+def retry_on_transient_error(max_retries=3, backoff=1.0):
+    """Decorator that retries a test on transient infrastructure errors."""
 
     def decorator(func):
         @functools.wraps(func)
@@ -91,8 +82,7 @@ def wrapper(*args, **kwargs):
                 except Exception as exc:
                     if attempt < max_retries and _is_transient_error(exc):
                         last_exc = exc
-                        delay = min(base_delay * (2**attempt), max_delay)
-                        time.sleep(delay)
+                        time.sleep(backoff * (attempt + 1))
                         continue
                     raise
             raise last_exc