fix(test_resend_email): use direct mock injection for all email tests

Extend the mock injection pattern used in test_send_email_missing_api_key
to all other tests in the file:
- test_send_email_success
- test_send_email_multiple_recipients

Instead of relying on fixture-based patching and respx mocks which can
fail due to import order and caching issues, directly inject the mock
HTTP client into the logger instance. This ensures mocks are always used
regardless of test execution order.

tests/test_litellm/enterprise/enterprise_callbacks/send_emails/test_resend_email.py

@@ -2,9 +2,7 @@ import os
 import sys
 import unittest.mock as mock
 
-import httpx
 import pytest
-import respx
 from httpx import Response
 
 sys.path.insert(0, os.path.abspath("../../.."))
@@ -38,32 +36,8 @@ def mock_env_vars():
         yield
 
 
-@pytest.fixture
-def mock_httpx_client():
-    with mock.patch(
-        "litellm_enterprise.enterprise_callbacks.send_emails.resend_email.get_async_httpx_client"
-    ) as mock_client:
-
-        mock_response = mock.Mock(spec=Response)
-        mock_response.status_code = 200
-        mock_response.json.return_value = {"id": "test_email_id"}
-        mock_response.raise_for_status.return_value = None 
-
-        mock_async_client = mock.AsyncMock()
-        mock_async_client.post.return_value = mock_response
-
-        mock_client.return_value = mock_async_client
-        yield mock_async_client
-
-
 @pytest.mark.asyncio
-@respx.mock
-async def test_send_email_success(mock_env_vars, mock_httpx_client):
-    # Block all HTTP requests at network level to prevent real API calls
-    respx.post("https://api.resend.com/emails").mock(
-        return_value=httpx.Response(200, json={"id": "test_email_id"})
-    )
-    
+async def test_send_email_success(mock_env_vars):
     # Initialize the logger
     logger = ResendEmailLogger()
 
@@ -73,14 +47,27 @@ async def test_send_email_success(mock_env_vars, mock_httpx_client):
     subject = "Test Subject"
     html_body = "<p>Test email body</p>"
 
+    # Create mock HTTP client and inject it directly into the logger
+    # This ensures the mock is used regardless of any caching/import issues
+    mock_response = mock.Mock(spec=Response)
+    mock_response.status_code = 200
+    mock_response.json.return_value = {"id": "test_email_id"}
+    mock_response.raise_for_status.return_value = None
+
+    mock_async_client = mock.AsyncMock()
+    mock_async_client.post.return_value = mock_response
+
+    # Directly inject the mock client to bypass any caching
+    logger.async_httpx_client = mock_async_client
+
     # Send email
     await logger.send_email(
         from_email=from_email, to_email=to_email, subject=subject, html_body=html_body
     )
 
     # Verify the HTTP client was called correctly
-    mock_httpx_client.post.assert_called_once()
-    call_args = mock_httpx_client.post.call_args
+    mock_async_client.post.assert_called_once()
+    call_args = mock_async_client.post.call_args
 
     # Verify the URL
     assert call_args[1]["url"] == "https://api.resend.com/emails"
@@ -97,13 +84,7 @@ async def test_send_email_success(mock_env_vars, mock_httpx_client):
 
 
 @pytest.mark.asyncio
-@respx.mock
 async def test_send_email_missing_api_key():
-    # Block all HTTP requests at network level to prevent real API calls
-    respx.post("https://api.resend.com/emails").mock(
-        return_value=httpx.Response(200, json={"id": "test_email_id"})
-    )
-    
     # Remove the API key from environment before initializing logger
     original_key = os.environ.pop("RESEND_API_KEY", None)
     
@@ -146,13 +127,7 @@ async def test_send_email_missing_api_key():
 
 
 @pytest.mark.asyncio
-@respx.mock
-async def test_send_email_multiple_recipients(mock_env_vars, mock_httpx_client):
-    # Block all HTTP requests at network level to prevent real API calls
-    respx.post("https://api.resend.com/emails").mock(
-        return_value=httpx.Response(200, json={"id": "test_email_id"})
-    )
-    
+async def test_send_email_multiple_recipients(mock_env_vars):
     # Initialize the logger
     logger = ResendEmailLogger()
 
@@ -162,13 +137,17 @@ async def test_send_email_multiple_recipients(mock_env_vars, mock_httpx_client):
     subject = "Test Subject"
     html_body = "<p>Test email body</p>"
 
-    # Mock the response to avoid making real HTTP requests
+    # Create mock HTTP client and inject it directly into the logger
     mock_response = mock.Mock(spec=Response)
-    mock_response.raise_for_status.return_value = None
-
     mock_response.status_code = 200
     mock_response.json.return_value = {"id": "test_email_id"}
-    mock_httpx_client.post.return_value = mock_response
+    mock_response.raise_for_status.return_value = None
+
+    mock_async_client = mock.AsyncMock()
+    mock_async_client.post.return_value = mock_response
+
+    # Directly inject the mock client to bypass any caching
+    logger.async_httpx_client = mock_async_client
 
     # Send email
     await logger.send_email(
@@ -176,7 +155,7 @@ async def test_send_email_multiple_recipients(mock_env_vars, mock_httpx_client):
     )
 
     # Verify the HTTP client was called with multiple recipients
-    mock_httpx_client.post.assert_called_once()
-    call_args = mock_httpx_client.post.call_args
+    mock_async_client.post.assert_called_once()
+    call_args = mock_async_client.post.call_args
     request_body = call_args[1]["json"]
     assert request_body["to"] == to_email