test(core): harden concurrent-mutation test for safe_json_dumps

- Loop 50 iterations to increase race trigger probability
- Catch all exceptions (not just RuntimeError) to avoid silent swallowing
- Assert result is a non-empty string (correctness check)

tests/test_litellm/litellm_core_utils/test_safe_json_dumps.py

@@ -177,28 +177,35 @@ def test_pydantic_base_model():
 
 def test_no_runtime_error_on_concurrent_dict_mutation():
     """safe_dumps must not raise RuntimeError when another thread mutates the dict."""
-    data = {f"key_{i}": f"value_{i}" for i in range(200)}
-    barrier = threading.Barrier(2, timeout=5)
-    errors = []
+    errors: list = []
 
-    def mutator():
-        barrier.wait()
-        for i in range(200, 400):
-            data[f"key_{i}"] = f"value_{i}"
+    for _ in range(50):
+        data = {f"key_{i}": f"value_{i}" for i in range(200)}
+        barrier = threading.Barrier(2, timeout=5)
+        results: list = []
 
-    def serializer():
-        barrier.wait()
-        try:
-            safe_dumps(data)
-        except RuntimeError as e:
-            if "dictionary changed size during iteration" in str(e):
+        def mutator():
+            barrier.wait()
+            for i in range(200, 400):
+                data[f"key_{i}"] = f"value_{i}"
+
+        def serializer():
+            barrier.wait()
+            try:
+                result = safe_dumps(data)
+                results.append(result)
+            except Exception as e:
                 errors.append(e)
 
-    t1 = threading.Thread(target=mutator)
-    t2 = threading.Thread(target=serializer)
-    t1.start()
-    t2.start()
-    t1.join(timeout=5)
-    t2.join(timeout=5)
+        t1 = threading.Thread(target=mutator)
+        t2 = threading.Thread(target=serializer)
+        t1.start()
+        t2.start()
+        t1.join(timeout=5)
+        t2.join(timeout=5)
 
-    assert not errors, "safe_dumps raised RuntimeError on concurrent mutation"
+        if results:
+            assert isinstance(results[0], str)
+            assert len(results[0]) > 0
+
+    assert not errors, f"safe_dumps raised {errors[0]!r} on concurrent mutation"