fix(test): add missing mock for get_vertex_ai_credentials

[jquinter]

Summary

Fixes test failure by adding missing mock for get_vertex_ai_credentials.

Problem

Test test_validate_environment_with_optional_params was failing with:

Exception: Unable to load vertex credentials from environment. 
Got=path/to/credentials.json

The test passes "path/to/credentials.json" as fake credentials, but the code tries to load this file for real, which:

1. Doesn't exist as a file
2. Isn't valid JSON
3. Causes an exception

Root Cause

The test test_validate_environment (line 92) correctly mocks get_vertex_ai_credentials:

with patch.object(self.config, 'get_vertex_ai_credentials', return_value=None):

But test_validate_environment_with_optional_params was missing this mock, causing it to try loading the fake credential file for real.

Solution

Added the same mock pattern to test_validate_environment_with_optional_params:

with patch.object(self.config, 'get_vertex_ai_credentials', return_value=None):
    headers = self.config.validate_environment(...)

Testing

pytest tests/.../test_vertex_ai_rerank_transformation.py::TestVertexAIRerankTransform::test_validate_environment_with_optional_params -v
======================== 1 passed in 0.18s ========================

Related

This test failure was reported on PR #21217, but NOT caused by PR #21217 (which only modifies Anthropic structured output tests). This is a missing mock in the test itself.

🤖 Generated with Claude Code

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Project	Deployment	Actions	Updated (UTC)
litellm	Ready	Preview, Comment	Feb 15, 2026 10:32pm

[greptile-apps]

Greptile Summary

This PR adds a patch.object mock for get_vertex_ai_credentials to test_validate_environment_with_optional_params, intended to prevent the test from trying to load a fake credential file path.

However, validate_environment in transformation.py calls self.safe_get_vertex_ai_credentials() (the non-mutating variant), not self.get_vertex_ai_credentials(). The added mock targets the wrong method and has no practical effect. The test passes because _ensure_access_token is already mocked via the @patch decorator on the test method, which intercepts the call before any real credential loading.

• The mock for get_vertex_ai_credentials should instead target safe_get_vertex_ai_credentials if the intent is to prevent credential string resolution
• The sibling test test_validate_environment_preserves_optional_params_for_get_complete_url (line 476) has the same pattern (fake credentials, no mock for the safe variant) and may have the same latent issue

Confidence Score: 3/5

• Low risk test-only change, but the mock targets the wrong method and has no effect on test behavior
• The change is a test-only fix with no production code impact, so it's safe to merge. However, the mock targets get_vertex_ai_credentials while the code under test calls safe_get_vertex_ai_credentials, meaning the mock is a no-op. The test passes due to the existing _ensure_access_token mock, not this new one. Score of 3 reflects that while harmless, the fix doesn't address its stated purpose.
• tests/test_litellm/llms/vertex_ai/rerank/test_vertex_ai_rerank_transformation.py — mock targets get_vertex_ai_credentials instead of safe_get_vertex_ai_credentials

Important Files Changed

Filename	Overview
tests/test_litellm/llms/vertex_ai/rerank/test_vertex_ai_rerank_transformation.py	Adds a mock for get_vertex_ai_credentials in test_validate_environment_with_optional_params, but validate_environment actually calls safe_get_vertex_ai_credentials — the mock targets the wrong method and has no effect. The test passes because _ensure_access_token is already mocked via the @patch decorator.

Sequence Diagram

sequenceDiagram
    participant Test as Test Method
    participant Config as VertexAIRerankConfig
    participant SafeGet as safe_get_vertex_ai_credentials
    participant GetCreds as get_vertex_ai_credentials
    participant EnsureToken as _ensure_access_token

    Note over GetCreds: MOCKED but never called
    Note over EnsureToken: MOCKED via decorator

    Test->>Config: validate_environment(optional_params)
    Config->>SafeGet: safe_get_vertex_ai_credentials(params)
    SafeGet-->>Config: credential string from optional_params
    Config->>EnsureToken: called with credential string
    EnsureToken-->>Config: mocked return value
    Config-->>Test: headers dict

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_{Last reviewed commit: a4cbb83}

[greptile-apps]

_{1 file reviewed, 1 comment}

_{Edit Code Review Agent Settings | Greptile}

[greptile-apps]

Mock targets wrong method

validate_environment (in transformation.py:80) calls self.safe_get_vertex_ai_credentials(litellm_params), not self.get_vertex_ai_credentials(...). Since safe_get_vertex_ai_credentials is the method actually invoked, this patch.object for get_vertex_ai_credentials has no effect — it mocks a method that is never called in this code path.

The test already works because _ensure_access_token is mocked via the @patch decorator on the test method, which intercepts the call before any real credential loading occurs.

If the intent is to prevent safe_get_vertex_ai_credentials from returning the fake credential string, the mock should target that method instead:

Suggested change

	with patch.object(self.config, 'get_vertex_ai_credentials', return_value=None):
	with patch.object(self.config, 'safe_get_vertex_ai_credentials', return_value=None):

Note: the same pattern may need to be applied to test_validate_environment_preserves_optional_params_for_get_complete_url (line 476) which also passes fake credentials without mocking.

[jquinter]

Closing this PR. The test failures were due to environment variable pollution from other tests, which was already fixed by PR #21268 that adds setup_method/teardown_method to clean environment variables.

As Greptile correctly identified, the mock added in this PR is ineffective - it mocks get_vertex_ai_credentials but the code actually calls safe_get_vertex_ai_credentials. The test passes because _ensure_access_token is already mocked via the @patch decorator, preventing any credential loading.

The tests now pass on main branch in isolation, confirming the environment cleanup in #21268 resolved the issue.