Enable local testing for all cachier backends with Docker

[shaypal5]

Description

This PR extends the MongoDB local testing solution (PR #285) to support all cachier backends (MongoDB, Redis, SQL, Memory, Pickle). It provides a unified interface for developers to test any combination of backends locally with Docker containers.

What's New

1. Unified Test Script (scripts/test-local.sh)

A comprehensive script that replaces the MongoDB-specific script with support for all backends:

• Flexible core selection: test individual backends, groups, or all
• Automatic dependency checking and installation
• Smart Docker container lifecycle management
• Support for unmarked general tests when running "all"

Usage examples:

# Test single backend
./scripts/test-local.sh mongo
./scripts/test-local.sh redis

# Test multiple backends
./scripts/test-local.sh mongo redis sql

# Test all backends (includes unmarked tests)
./scripts/test-local.sh all

# Test groups
./scripts/test-local.sh external  # mongo, redis, sql
./scripts/test-local.sh local     # memory, pickle

2. All-Cores Docker Compose (scripts/docker-compose.all-cores.yml)

Comprehensive docker-compose configuration with all external services:

• MongoDB (port 27017)
• Redis (port 6379)
• PostgreSQL (port 5432)
• Health checks for all services
• Unified network configuration

3. Enhanced Makefile Targets

New make commands for convenience:

make test-local CORES="mongo redis"  # Test specific cores
make test-all-local                   # Test all backends
make test-external                    # Test external backends only
make test-redis-local                 # Test Redis only
make test-sql-local                   # Test SQL only
make services-start                   # Start all containers
make services-stop                    # Stop all containers

4. Backend-Specific Improvements

• Separated MongoDB dependencies into tests/mongodb_requirements.txt
• Fixed SQL test import isolation issue
• Support for multiple pytest markers per core (e.g., pickle uses "pickle or maxage")
• Automatic installation of backend-specific dependencies

5. Documentation Updates

• Comprehensive guide in scripts/README-local-testing.md
• Updated CLAUDE.md with new testing commands
• Updated CI workflow to use mongodb_requirements.txt

Key Features

1. Unified Interface: Single script handles all backends
2. Smart Dependencies: Auto-installs only required dependencies
3. Flexible Selection: Test any combination of backends
4. Portable: Works with older bash versions (no associative arrays)
5. Complete Coverage: Runs all 144 tests when using "all" option

Breaking Changes

• Removed scripts/test-mongo-local.sh (replaced by unified script)
• Removed scripts/docker-compose.mongodb.yml (replaced by all-cores version)

Testing

• Tested locally on macOS with all backends
• All 144 tests pass with ./scripts/test-local.sh all
• Handles missing Docker gracefully
• Proper cleanup even on test failure

Future Enhancements

• Add support for additional backends (MySQL, Elasticsearch)
• Parallel test execution for multiple backends
• Performance benchmarking mode