Filesys Package

This package provides file system scanning and tracking functionality for both local file systems and Google Drive.

Overview

The filesys package contains:

• Scanner Interface: Defines the interface for scanning directories and returning tree nodes
• File System Scanner: Implementation for local Unix file systems
• Google Drive Scanner: Implementation for Google Drive directories
• Context-Aware Tracker: Tracks files/directories based on the current context (local or gdrive)

Mocking with Mockery

This package uses mockery to generate mocks for testing. The mocks are generated for interfaces to enable unit testing without external dependencies.

Setup

1. Install mockery:

   go install github.com/vektra/mockery/v3@latest

2. Install gomock dependency (required for expecter-style mocks):

   go get go.uber.org/mock/gomock

3. Generate mocks:

   # From the project root
   mockery

   This will generate mocks based on the .mockery.yaml configuration file in the project root.

   Note: Mock generation requires network access to download Go dependencies if needed.

Generated Mocks

The following mocks are generated in the mocks/ directory:

• mocks/services/mock_GDriveServiceInterface.go - Mock for Google Drive service
• mocks/filesys/mock_Scanner.go - Mock for Scanner interface
• mocks/filesys/mock_ScannableNode.go - Mock for ScannableNode interface
• mocks/filesys/mock_Tracker.go - Mock for Tracker interface
• mocks/repository/filesys/mock_ContextRepository.go - Mock for ContextRepository interface
• mocks/storage/ - Mocks for TreeReader, TreeWriter, TreeRW, RWFactory
• mocks/file/ - Mocks for NodeInformable, SerializableNode, TagsPrinter, NodePrinter, IdPrinter
• mocks/printer/ - Mocks for ListPrintable, PrintingContext
• mocks/ds/ - Mocks for TreeIterable, NodeIterable, InfoSerializer, TreeNodeInformable

All mocks use package mocks and can be imported from their respective subdirectories.

Using Mocks in Tests

Example: Testing with MockGDriveServiceInterface

package cmd_test

import (
    "context"
    "testing"
    
    "github.com/heroku/self/MetaManager/internal/filesys"
    "github.com/heroku/self/MetaManager/internal/services"
    servicemocks "github.com/heroku/self/MetaManager/mocks/services"
    "github.com/stretchr/testify/require"
    "github.com/stretchr/testify/mock"
)

func TestTrackGDrive(t *testing.T) {
    // Create a mock GDrive service
    mockSvc := servicemocks.NewMockGDriveServiceInterface(t)
    
    // Set up expectations using testify mock pattern
    mockSvc.On("ResolvePath", mock.Anything, "Folder1").
        Return("folder1", nil)
    
    mockSvc.On("ListFolder", mock.Anything, "folder1").
        Return([]services.RootEntry{
            {Id: "sub1", Name: "Sub", IsFolder: true, MimeType: services.DriveFolderMimeType},
            {Id: "file1", Name: "file1.txt", IsFolder: false, MimeType: "text/plain"},
        }, nil)
    
    // Create scanner with mock
    scanner := filesys.NewGDriveScanner(mockSvc)
    
    // Test the functionality
    tree, err := scanner.TrackGDrive(context.Background(), "/Folder1", false)
    require.NoError(t, err)
    require.NotNil(t, tree)
    
    // Assert all expectations were met
    mockSvc.AssertExpectations(t)
}

Note: The mockery-generated mocks use go.uber.org/mock/gomock for expecter-style mocking. Make sure to add this dependency:

go get go.uber.org/mock/gomock

Example: Testing with MockScanner

import (
    filesysmocks "github.com/heroku/self/MetaManager/mocks/filesys"
    "github.com/stretchr/testify/mock"
)

func TestContextAwareTracker(t *testing.T) {
    // Create a mock scanner
    mockScanner := filesysmocks.NewMockScanner(t)
    
    // Set up expectations
    mockScanner.On("Scan", "/some/path").
        Return(&ds.TreeNode{...}, nil)
    
    // Use the mock in your test
    // ...
    
    // Assert all expectations were met
    mockScanner.AssertExpectations(t)
}

Regenerating Mocks

After modifying interfaces, regenerate the mocks:

mockery

Or regenerate specific interfaces using the interface name:

mockery --name GDriveServiceInterface --dir internal/services

Note: Mock generation requires network access if Go dependencies need to be downloaded.

Mockery Configuration

The mockery configuration is stored in .mockery.yaml at the project root. Key settings:

• template: testify - Uses the testify mock template (supports expecter-style mocks)
• template-data.with-expecter: true - Generates expecter-style mocks (gomock compatible)
• structname: "Mock{{.InterfaceName}}" - Naming convention for generated mocks
• dir: "mocks" - Output directory for mocks (relative to interface package)
• filename: "{{.MockName}}.go" - Filename pattern for generated mocks

The configuration generates mocks in subdirectories under mocks/:

• GDriveServiceInterface in mocks/services/
• Scanner, ScannableNode, and Tracker in mocks/filesys/
• ContextRepository in mocks/repository/filesys/
• Storage interfaces in mocks/storage/
• File interfaces in mocks/file/
• Printer interfaces in mocks/printer/
• Data structure interfaces in mocks/ds/

All mocks use package mocks and can be imported from their respective subdirectories.

Best Practices

1. Always use mocks in tests - Don't rely on real external services (like Google Drive API) in unit tests
2. Set up expectations - Use EXPECT() to define what methods should be called and what they should return
3. Verify calls - Use gomock.Controller to ensure all expected calls were made
4. Keep mocks in sync - Regenerate mocks after interface changes
5. Commit mocks - Include generated mock files in version control for consistency

Troubleshooting

Issue: Mocks not generating

• Solution: Ensure mockery is installed and .mockery.yaml is in the project root

Issue: Import errors in generated mocks

• Solution: Run go mod tidy after generating mocks

Issue: Mocks out of date

• Solution: Regenerate mocks with mockery command

Package Structure

internal/filesys/
├── scanner.go              # Scanner interface and factory
├── file_scanner.go         # Local file system scanner
├── gdrive_scanner.go       # Google Drive scanner
├── track.go                # Context-aware tracker
├── mocks/                  # Generated mocks (git tracked)
│   ├── MockScanner.go
│   └── MockScannableNode.go
└── README.md               # This file

Related Packages

• internal/services - Google Drive service implementation
• internal/data - Tree data structures and management
• internal/file - File node definitions
• internal/repository/filesys - Context repository for file system contexts