test: isolate bedrock image request formatting from suite state

tests/test_litellm/conftest.py

@@ -29,6 +29,42 @@ from litellm.llms.custom_httpx.async_client_cleanup import (
 from litellm.proxy.db import tool_registry_writer as tool_registry_writer_module
 
 
+def _reset_module_level_aws_auth_caches():
+    """
+    Clear module-level AWS auth state that can survive between tests.
+
+    Bedrock/SageMaker handlers are instantiated once at import time and cache
+    resolved credentials on the handler instance. If a previous test resolves an
+    invalid or different auth flow, later tests can reuse that cached state and
+    bypass their local monkeypatched env setup.
+    """
+    for module_name in (
+        "litellm.main",
+        "litellm.files.main",
+        "litellm.rerank_api.main",
+        "litellm.realtime_api.main",
+    ):
+        try:
+            module = importlib.import_module(module_name)
+        except Exception:
+            continue
+        for attr_name in dir(module):
+            obj = getattr(module, attr_name)
+            iam_cache = getattr(obj, "iam_cache", None)
+            if iam_cache is None:
+                continue
+            flush_cache = getattr(iam_cache, "flush_cache", None)
+            if callable(flush_cache):
+                flush_cache()
+
+    try:
+        import boto3
+
+        boto3.DEFAULT_SESSION = None
+    except Exception:
+        pass
+
+
 @pytest.fixture(scope="session")
 def isolated_aws_credentials_dir(tmp_path_factory):
     aws_dir = tmp_path_factory.mktemp("aws-config")
@@ -54,6 +90,12 @@ def isolate_host_aws_config(monkeypatch, isolated_aws_credentials_dir):
     monkeypatch.delenv("AWS_DEFAULT_PROFILE", raising=False)
     monkeypatch.delenv("AWS_CONTAINER_CREDENTIALS_FULL_URI", raising=False)
     monkeypatch.delenv("AWS_CONTAINER_CREDENTIALS_RELATIVE_URI", raising=False)
+    monkeypatch.delenv("AWS_SESSION_TOKEN", raising=False)
+    monkeypatch.delenv("AWS_ROLE_ARN", raising=False)
+    monkeypatch.delenv("AWS_WEB_IDENTITY_TOKEN_FILE", raising=False)
+    monkeypatch.delenv("AWS_BEARER_TOKEN_BEDROCK", raising=False)
+    monkeypatch.delenv("AWS_REGION_NAME", raising=False)
+    monkeypatch.delenv("AWS_DEFAULT_REGION", raising=False)
 
 
 def _run_coroutine_if_needed(result):
@@ -196,6 +238,7 @@ def isolate_litellm_state():
     if hasattr(litellm, "in_memory_llm_clients_cache"):
         litellm.in_memory_llm_clients_cache.flush_cache()
     image_handling_module.in_memory_cache.flush_cache()
+    _reset_module_level_aws_auth_caches()
 
     # Clear all callback lists to prevent cross-test contamination
     if hasattr(litellm, 'callbacks'):
@@ -228,6 +271,7 @@ def isolate_litellm_state():
     if hasattr(litellm, "in_memory_llm_clients_cache"):
         litellm.in_memory_llm_clients_cache.flush_cache()
     image_handling_module.in_memory_cache.flush_cache()
+    _reset_module_level_aws_auth_caches()
     current_module_level_client = litellm.__dict__.get("module_level_client")
     current_module_level_aclient = litellm.__dict__.get("module_level_aclient")
 

tests/test_litellm/test_main.py

@@ -18,6 +18,10 @@ import litellm
 from litellm import main as litellm_main
 
 
+async def _async_fake_bedrock_image_details(image_url):
+    return "ZmFrZS1pbWFnZQ==", "image/png"
+
+
 @pytest.fixture(autouse=True)
 def clear_client_cache():
     """
@@ -166,12 +170,31 @@ def test_completion_missing_role(openai_api_response):
 async def test_url_with_format_param(model, sync_mode, monkeypatch):
     from litellm import acompletion, completion
     from litellm.llms.custom_httpx.http_handler import AsyncHTTPHandler, HTTPHandler
+    from litellm.litellm_core_utils.prompt_templates import factory as prompt_factory
 
     if sync_mode:
         client = HTTPHandler()
     else:
         client = AsyncHTTPHandler()
 
+    # This test is about request shaping, not live image downloads. Stub the
+    # URL->image conversion helpers so suite-level network/client state from
+    # earlier tests cannot prevent the mocked provider client from being hit.
+    fake_base64_image = "data:image/png;base64,ZmFrZS1pbWFnZQ=="
+    monkeypatch.setattr(
+        prompt_factory, "convert_url_to_base64", lambda url: fake_base64_image
+    )
+    monkeypatch.setattr(
+        prompt_factory.BedrockImageProcessor,
+        "get_image_details",
+        staticmethod(lambda image_url: ("ZmFrZS1pbWFnZQ==", "image/png")),
+    )
+    monkeypatch.setattr(
+        prompt_factory.BedrockImageProcessor,
+        "get_image_details_async",
+        staticmethod(_async_fake_bedrock_image_details),
+    )
+
     args = {
         "model": model,
         "messages": [