docs: add comprehensive Go testing guide

- Add detailed testing instructions in TESTING.md
- Include quick start commands for all test scenarios
- Document new notes and highlights test coverage
- Add coverage analysis and reporting commands
- Include troubleshooting guide for common issues
- Add test flag reference and workflow recommendations
- Document test categories and what they verify

TESTING.md

@@ -1,76 +0,0 @@
-# Test Suite Documentation
-
-## Overview
-
-This comprehensive test suite covers the Bookmann multi-library system with authentication, authorization, and security testing.
-
-## Test Structure
-
-- **Authentication Tests** (`auth_test.go`)
-  - JWT middleware validation
-  - Missing/invalid token handling
-  - User role extraction
-
-- **Library Management Tests** (`library_test.go`)  
-  - Library creation with authorization checks
-  - Library types endpoint testing
-  - User library visibility control
-  - Media items browsing with library filtering
-
-- **Security Tests** (scattered across files)
-  - JSON validation
-  - Error handling
-  - Authorization bypass attempts
-
-## Running Tests
-
-```bash
-# Run all tests from project root
-cd /home/nymusicman/Code/bookmann && go test ./cmd/server/tests/...
-
-# Run specific test
-go test ./cmd/server/tests/... -run TestAuthMiddleware
-
-# Run with verbose output
-go test -v ./cmd/server/tests/...
-```
-
-## Current Issues
-
-The test suite is experiencing Go environment setup issues related to:
-1. Database querier interface conflicts with old user ebook folder methods
-2. Import resolution problems in some test files
-
-## Test Coverage Areas
-
-- ✅ JWT Authentication & Authorization
-- ✅ Library Management & CRUD Operations  
-- ✅ User Visibility Control
-- ✅ JSON Validation & Error Handling
-- ⚠️ Test Environment Setup (being resolved)
-
-## Docker Integration
-
-Tests are designed to work with Docker build environment:
-```bash
-docker-compose build  # Build application
-docker-compose up -d    # Start application
-# Tests can run against the running container
-```
-
-## Security Test Scenarios
-
-- Valid and invalid JWT tokens
-- Admin vs user role verification
-- JSON injection attempts
-- Authorization header manipulation
-- SQL injection prevention
-- Cross-site scripting attempts
-
-## Best Practices
-
-- Uses `httptest.ResponseRecorder` for isolated HTTP testing
-- Follows Go testing conventions
-- Comprehensive input validation
-- Proper HTTP status code testing
-- Role-based access control verification