Add unit tests for azure.ai.finetune extension

[saanikaguptamicrosoft]

Adds comprehensive unit test coverage for the azure.ai.finetune extension and enables CI test execution.

CI/Pipeline
Add ci-test.ps1 to run unit tests with gotestsum for better output formatting
Enable test execution in pipeline (SkipTests: false)
Add workingDirectory to the "Run tests" step in build-azd-extension.yml

Test Coverage
464+ tests across all packages
All tests pass on Windows, Linux, and macOS
Tests are deterministic (not flaky) and use mocks for external dependencies

[Copilot]

Pull request overview

This pull request adds comprehensive unit test coverage for the azure.ai.finetune extension. The tests cover models, utilities, services, providers, and command functionality with table-driven patterns and thorough edge case testing.

Changes:

• Adds 16 new test files covering all major components of the azure.ai.finetune extension
• Adds 13 testdata YAML files for parser validation testing
• Fixes spacing alignment for a constant in environment.go (formatting only)

Reviewed changes

Copilot reviewed 28 out of 29 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
pkg/models/views_test.go	Tests for view model transformations and formatting helpers
pkg/models/requests_test.go	Tests for request structure validation
pkg/models/finetune_test.go	Tests for fine-tuning job models, validation, and JSON marshaling
pkg/models/errors_test.go	Tests for error handling and error code uniqueness
pkg/models/deployment_test.go	Tests for deployment models and configurations
internal/utils/time_test.go	Tests for time formatting and duration calculations
internal/utils/status_test.go	Tests for job status symbols and terminal status detection
internal/utils/retry_test.go	Tests for retry logic with various failure scenarios
internal/utils/parser_test.go	Tests for YAML config parsing with valid and invalid inputs
internal/utils/output_test.go	Tests for output formatting (table, JSON, YAML)
internal/utils/environment_test.go	Tests for environment constant validation
internal/utils/common_test.go	Tests for file path utilities
internal/services/finetune_service_test.go	Tests for fine-tuning service with mock providers
internal/providers/azure/provider_test.go	Tests for Azure provider validation
internal/cmd/init_test.go	Tests for initialization command and resource ID parsing
internal/utils/environment.go	Formatting fix: aligns EnvFinetuningTokenScope constant spacing
internal/utils/testdata/*.yaml	Test fixture files for parser validation tests