Test Coverage Assessment for PR #71

Summary

This PR adds a gro drive download command with export functionality for Google Workspace files. The test coverage is adequate for the new code, following established patterns in the codebase.

What's Well Tested

internal/drive/files.go (new functions):

• GetExportMimeType() - comprehensive tests covering all file types (Document, Spreadsheet, Presentation, Drawing), error cases for unsupported formats, and invalid source types
• GetSupportedExportFormats() - tested for all workspace file types plus the nil return case
• GetFileExtension() - all 11 supported formats tested plus unknown format edge case

internal/cmd/drive/download.go:

• determineOutputPath() - well-tested helper function with 8 test cases covering user-specified paths, format-based extension replacement, and various export formats
• Command structure tests (flags, arguments, descriptions) - consistent with other commands in the codebase

What's Not Tested (and why it's acceptable)

runDownload() function (lines 52-121):

• This is the main command runner that orchestrates API calls. It's not unit tested, which is consistent with other commands in this codebase (e.g., list, search, get commands also don't test their run* functions).
• Testing this function would require mocking the Google Drive API client, which is not done anywhere in the existing codebase.
• The business logic it uses (IsGoogleWorkspaceFile, GetExportMimeType, determineOutputPath) is tested.

Client.DownloadFile() and Client.ExportFile() (lines 76-103 in client.go):

• These are thin wrappers around Google's API client. Existing client methods (ListFiles, GetFile) also have no unit tests.
• Testing these would require extensive mocking of the Google Drive API, which provides limited value for read-only pass-through methods.

Coverage Metrics

These numbers are reasonable given that:

1. The untested code is primarily API orchestration
2. Pure functions with business logic are well covered
3. The pattern matches existing commands in the codebase

Verdict

The test coverage is acceptable. The PR:

• Tests all pure functions with meaningful logic
• Tests edge cases and error conditions
• Follows established testing patterns in the codebase
• Doesn't introduce untested business logic

No additional tests are required for this PR to merge safely.