# VLLM GCE Tests Summary

## Overview
Added comprehensive unit and mock e2e tests for the vllm GCE module that test the core functionality without requiring actual GCE resources.

## Tests Added

### up.rs Tests

#### Unit Tests (9 tests)
1. **`test_load_cloud_config`** - Validates basic cloud-config generation
2. **`test_load_cloud_config_with_model`** - Tests custom model configuration
3. **`test_load_cloud_config_with_custom_name`** - Tests custom instance naming
4. **`test_indent_single_line`** - Tests indent helper function for single lines
5. **`test_indent_multiple_lines`** - Tests multi-line indentation
6. **`test_indent_empty_string`** - Tests edge case with empty strings
7. **`test_up_args_builder_defaults`** - Validates default argument values
8. **`test_up_args_builder_custom_values`** - Tests custom argument configuration

#### Mock E2E Tests (7 tests)
9. **`mock_instance_creation_success`** - Simulates successful GCE instance creation
10. **`mock_instance_creation_failure`** - Tests error handling during creation
11. **`test_cloud_config_contains_required_fields`** - Validates cloud-config structure
12. **`test_cloud_config_uses_defaults`** - Tests default value handling
13. **`test_cloud_config_default_model`** - Validates default model selection
14. **`test_instance_name_generation`** - Tests instance naming logic
15. **`test_cloud_config_includes_setup_script`** - Validates setup script inclusion

### down.rs Tests

#### Unit Tests (2 tests)
1. **`test_down_returns_ok`** - Validates deletion function completes
2. **`test_down_with_namespace_ignored`** - Tests K8s compatibility parameter

#### Mock E2E Tests (4 tests)
3. **`mock_instance_deletion_success`** - Simulates successful instance deletion
4. **`mock_instance_deletion_failure`** - Tests deletion error handling
5. **`mock_multiple_instance_deletions`** - Tests batch deletion tracking
6. **`test_zone_default_value`** - Validates zone default logic

## Test Coverage

The tests cover:
- ✅ Cloud-config generation and templating
- ✅ Environment variable substitution (HF_TOKEN, MODEL, etc.)
- ✅ Instance configuration (machine type, GPUs, disks)
- ✅ Builder pattern validation
- ✅ UUID generation for unique instances
- ✅ Mock GCE API interactions (create/delete)
- ✅ Error handling scenarios

## Running the Tests

```bash
cargo test --package spnl --lib --no-default-features --features gce -- gce::vllm --nocapture
```

## Test Infrastructure

### Mock Test Setup
- **`MockGceClient`**: Simulates GCE instance creation with success/failure modes
- **`MockGceDeleteClient`**: Simulates GCE instance deletion with tracking

### Current Implementation Notes
The current implementation uses `std::env::var()` to read configuration from environment variables. The tests avoid manipulating environment variables to prevent unsafe operations and test isolation issues.

## TODO: Future Refactoring and Enhancements

### 1. Refactor Environment Variable Handling ✅ COMPLETED
**Priority: High**
**Resolved in:** [PR #744](https://github.com/IBM/spnl/pull/744)

~~Currently, both `up.rs` and `down.rs` read configuration directly from environment variables using `std::env::var()`. This should be refactored to use clap's environment variable support.~~

**Action Items:**
- [x] Create `args.rs` module in `gce/vllm/`
- [x] Define configuration structs using clap's `#[arg(env = "...")]` attribute
- [x] Move all environment variable reading to args structs:
  - `GCP_PROJECT` / `GOOGLE_CLOUD_PROJECT`
  - `GCP_SERVICE_ACCOUNT`
  - `GCE_REGION` (default: "us-west1")
  - `GCE_ZONE` (default: "us-west1-a")
  - `GCE_MACHINE_TYPE` (default: "g2-standard-4")
  - `GCS_BUCKET` (default: "spnl-test")
  - `SPNL_GITHUB` (default: "https://github.com/IBM/spnl.git")
  - `GITHUB_SHA`
  - `GITHUB_REF`
  - `VLLM_ORG` (default: "neuralmagic")
  - `VLLM_REPO` (default: "vllm")
  - `VLLM_BRANCH` (default: "llm-d-release-0.4")
- [x] Update `UpArgs` to include these configuration fields
- [x] Update `down()` to accept configuration args instead of reading env vars directly
- [x] Update `load_cloud_config()` to accept configuration from args

**Benefits:**
- ✅ Cleaner separation of concerns
- ✅ Better testability (can pass different configs without env vars)
- ✅ Consistent with clap patterns used elsewhere in the codebase
- ✅ Type-safe configuration with validation

### 2. Enhanced Test Coverage for Configuration Overrides
**Priority: Medium**

Once the refactoring is complete, add tests that verify configuration overrides work correctly.

**Action Items:**
- [ ] Test default values are used when no overrides provided
- [ ] Test each configuration field can be overridden individually
- [ ] Test multiple overrides work together correctly
- [ ] Test invalid configurations are rejected appropriately
- [ ] Test zone/region combinations
- [ ] Test machine type validation

### 3. Additional Mock E2E Tests
**Priority: Medium**

Expand mock testing to cover more scenarios:

**Action Items:**
- [ ] **Serial Port Log Streaming**: Mock the `get_serial_port_output()` API calls
- [ ] **Instance Status Polling**: Test waiting for instance to be ready
- [ ] **Network Configuration**: Test IP address retrieval and display
- [ ] **Error Recovery**: Test retry logic and error handling
- [ ] **Timeout Scenarios**: Test behavior when operations take too long
- [ ] **Concurrent Operations**: Test multiple instances being managed

### 4. Integration with Real GCE API (Optional)
**Priority: Low**

For CI/CD environments with GCE access:

**Action Items:**
- [ ] Add integration test flag (e.g., `--features gce-integration`)
- [ ] Create test fixtures for real GCE operations
- [ ] Add cleanup logic to remove test instances
- [ ] Document required GCE permissions and setup

### 5. Implement Full `down()` Functionality
**Priority: Medium**

Currently, `down()` only prints instructions. Implement actual deletion:

**Action Items:**
- [ ] Implement GCE instance deletion using `google-cloud-compute-v1`
- [ ] Add proper error handling for deletion failures
- [ ] Add tests for deletion edge cases (instance not found, etc.)
- [ ] Add confirmation prompt for safety
- [ ] Add force-delete option

### 6. Code Quality Improvements
**Priority: Low**

**Action Items:**
- [ ] Add documentation comments for all public functions
- [ ] Add examples in doc comments
- [ ] Consider extracting cloud-config generation to separate module
- [ ] Add validation for instance names (GCE naming rules)
- [ ] Add validation for machine types and zones

## Test Plan Summary

### Phase 1: Refactoring (Current Priority)
1. Create `args.rs` with clap-based configuration
2. Refactor `up.rs` and `down.rs` to use args
3. Update existing tests to use new args pattern
4. Add configuration override tests

### Phase 2: Enhanced Testing
1. Add mock tests for serial port log streaming
2. Add mock tests for instance status polling
3. Add error handling and edge case tests
4. Add timeout and retry tests

### Phase 3: Production Readiness
1. Implement full `down()` functionality
2. Add integration tests (optional)
3. Add comprehensive documentation
4. Add validation and safety checks

## Inspiration

These tests follow the same pattern as the K8s vLLM tests, using mock clients to simulate API interactions without requiring actual cloud resources.