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+# Backend Test Plan
+
+## Overview
+This test plan is designed for iterative execution using sub-agents, with each sub-agent handling a specific phase to avoid exceeding the 300,000 token context limit. Each phase focuses on a distinct subsystem and includes specific test cases and verification steps.
+
+## Test Phases
+
+### Phase 1: Database & Migration Tests
+**Scope:** Alembic migrations, database schema, model relationships
+**Sub-agent Task:** Verify all migrations run correctly and database schema is consistent
+
+#### Test Cases:
+1. **Migration 000 (Empty)**
+   - Verify migration exists and is empty
+   - Check downgrade/upgrade functions exist
+
+2. **Migration 001 (Initial User Schema)**
+   - Run migration upgrade
+   - Verify all 16 tables created:
+     - `mtgonline_users` (base table)
+     - `mtgonline_decklist_files` (base table)
+     - `mtgonline_rooms` (base table)
+     - `user_sessions`
+     - `deck_versions`
+     - `game_replays`
+     - `replay_players`
+     - `game_outcomes`
+     - `user_statistics`
+     - `user_card_collection`
+     - `card_wishlist`
+     - `user_groups`
+     - `group_members`
+     - `group_chat_messages`
+     - `user_networks`
+     - `network_members`
+     - `user_preferences`
+     - `user_activity_log`
+   - Verify foreign key constraints
+   - Verify indexes created
+   - Verify unique constraints
+   - Run migration downgrade
+   - Verify all tables dropped
+
+3. **Migration 002 (User Deck Building Tables)**
+   - Run migration upgrade
+   - Verify tables created:
+     - `mtgonline_decklist_cards`
+     - `mtgonline_decklist_precedents`
+     - `mtgonline_decklist_suggestions`
+   - Verify foreign keys to `mtgonline_decklist_files`
+   - Run migration downgrade
+   - Verify tables dropped
+
+4. **Migration 003 (MTG Cards Table)**
+   - Run migration upgrade
+   - Verify `mtgonline_cards` table created
+   - Verify columns and indexes
+   - Run migration downgrade
+   - Verify table dropped
+
+5. **Migration 004 (Card Import Table)**
+   - Run migration upgrade
+   - Verify `mtgonline_card_imports` table created
+   - Verify foreign key to `mtgonline_users`
+   - Run migration downgrade
+   - Verify table dropped
+
+6. **Schema Consistency Checks**
+   - Verify all foreign keys reference existing tables
+   - Verify no circular dependencies
+   - Verify all tables have proper indexes
+   - Verify unique constraints are valid
+
+**Verification:** All migrations run successfully in order, schema is consistent, no orphaned foreign keys.
+
+---
+
+### Phase 2: Model Layer Tests
+**Scope:** SQLAlchemy models, relationships, validation
+**Sub-agent Task:** Verify all model definitions are correct and consistent
+
+#### Test Cases:
+1. **User Data Models (`app/models/user_data.py`)**
+   - Verify `User` model matches `mtgonline_users` table
+   - Verify all columns defined
+   - Verify relationships defined
+   - Check for missing fields
+
+2. **User Deck Models (`app/models/user_deck.py`)**
+   - Verify `DecklistFile`, `DecklistCard`, `DecklistPrecedent`, `DecklistSuggestion` models
+   - Verify foreign key relationships
+   - Verify cascade delete behavior
+   - Check for missing fields
+
+3. **Card Import Models (`app/models/user_card_import.py`)**
+   - Verify `CardImport` model
+   - Verify foreign key to `mtgonline_users`
+   - Check for missing fields
+
+4. **Game Models (`app/models/game.py`)**
+   - Verify `Game`, `GamePlayer`, `GameCard`, `GameAction`, `GameLog` models
+   - Verify relationships
+   - Check for missing fields
+
+5. **MTG Card Models (`app/models/mtg_card.py`)**
+   - Verify `MtgonlineCard`, `CardPriceHistory` models
+   - Verify relationships
+   - Check for missing fields
+
+6. **Model Consistency**
+   - Verify all models have proper `__tablename__`
+   - Verify all foreign keys reference correct tables
+   - Verify all relationships are bidirectional where needed
+   - Check for missing imports
+   - Verify model imports in `app/models/__init__.py`
+
+**Verification:** All models compile without errors, relationships are correct, no missing fields.
+
+---
+
+### Phase 3: Schema Layer Tests
+**Scope:** Pydantic schemas, request/response validation
+**Sub-agent Task:** Verify all schema definitions are correct
+
+#### Test Cases:
+1. **User Data Schemas (`app/schemas/user_data_schemas.py`)**
+   - Verify `UserCreate`, `UserUpdate`, `UserResponse` schemas
+   - Verify all required fields
+   - Check for missing validation
+
+2. **User Deck Schemas (`app/schemas/user_deck_schemas.py`)**
+   - Verify `DecklistFileCreate`, `DecklistFileUpdate`, `DecklistFileResponse`
+   - Verify `DecklistCardCreate`, `DecklistCardUpdate`, `DecklistCardResponse`
+   - Verify `DecklistPrecedentCreate`, `DecklistPrecedentUpdate`, `DecklistPrecedentResponse`
+   - Verify `DecklistSuggestionCreate`, `DecklistSuggestionUpdate`, `DecklistSuggestionResponse`
+   - Check for missing fields
+
+3. **Card Import Schemas (`app/schemas/card_import_schemas.py`)**
+   - Verify `CardImportCreate`, `CardImportResponse`
+   - Verify `CardImportStatusResponse`, `CardImportSummaryResponse`
+   - Check for missing fields
+
+4. **Game Schemas (`app/schemas/game_schemas.py`)**
+   - Verify `GameCreate`, `GameUpdate`, `GameResponse`
+   - Verify `GamePlayerCreate`, `GamePlayerResponse`
+   - Verify `GameCardCreate`, `GameCardResponse`
+   - Verify `GameActionCreate`, `GameActionResponse`
+   - Verify `GameLogCreate`, `GameLogResponse`
+   - Check for missing fields
+
+5. **MTG Card Schemas (`app/schemas/mtg_card_schemas.py`)**
+   - Verify `MtgonlineCardCreate`, `MtgonlineCardUpdate`, `MtgonlineCardResponse`
+   - Verify `CardPriceHistoryCreate`, `CardPriceHistoryResponse`
+   - Check for missing fields
+
+6. **Schema Consistency**
+   - Verify all schemas have proper `model_config`
+   - Verify required vs optional fields
+   - Check for missing imports
+   - Verify schema imports in `app/schemas/__init__.py`
+
+**Verification:** All schemas compile without errors, validation rules are correct, no missing fields.
+
+---
+
+### Phase 4: Router Layer Tests
+**Scope:** FastAPI routers, endpoint definitions, dependencies
+**Sub-agent Task:** Verify all router definitions are correct
+
+#### Test Cases:
+1. **User Data Router (`app/routers/user_data.py`)**
+   - Verify all endpoints defined
+   - Verify request/response schemas
+   - Verify dependencies (auth, etc.)
+   - Check for missing endpoints
+
+2. **Deck Router (`app/routers/decks.py`)**
+   - Verify all endpoints defined
+   - Verify request/response schemas
+   - Verify dependencies
+   - Check for missing endpoints
+
+3. **Card Import Router (`app/routers/card_import.py`)**
+   - Verify all endpoints defined
+   - Verify request/response schemas
+   - Verify dependencies
+   - Check for missing endpoints
+
+4. **Game Router (`app/routers/game.py`)**
+   - Verify all endpoints defined
+   - Verify request/response schemas
+   - Verify dependencies
+   - Check for missing endpoints
+
+5. **MTG Card Router (`app/routers/mtg_card.py`)**
+   - Verify all endpoints defined
+   - Verify request/response schemas
+   - Verify dependencies
+   - Check for missing endpoints
+
+6. **Router Consistency**
+   - Verify all routers imported in `app/main.py`
+   - Verify prefix paths are correct
+   - Verify tag assignments
+   - Check for missing imports
+
+**Verification:** All routers compile without errors, endpoints are properly defined, no missing imports.
+
+---
+
+### Phase 5: Service Layer Tests
+**Scope:** Business logic, service functions
+**Sub-agent Task:** Verify all service implementations are correct
+
+#### Test Cases:
+1. **User Service (`app/services/user_service.py`)**
+   - Verify all functions defined
+   - Verify function signatures
+   - Check for missing implementations
+
+2. **Deck Service (`app/services/deck_service.py`)**
+   - Verify all functions defined
+   - Verify function signatures
+   - Check for missing implementations
+
+3. **Card Import Service (`app/services/card_import_service.py`)**
+   - Verify all functions defined
+   - Verify function signatures
+   - Check for missing implementations
+
+4. **Game Service (`app/services/game_service.py`)**
+   - Verify all functions defined
+   - Verify function signatures
+   - Check for missing implementations
+
+5. **MTG Card Service (`app/services/mtg_card_service.py`)**
+   - Verify all functions defined
+   - Verify function signatures
+   - Check for missing implementations
+
+6. **Service Consistency**
+   - Verify all services imported where needed
+   - Verify function calls match implementations
+   - Check for missing imports
+
+**Verification:** All services compile without errors, functions are properly implemented, no missing imports.
+
+---
+
+### Phase 6: Utility & Helper Tests
+**Scope:** Utility functions, helpers, constants
+**Sub-agent Task:** Verify all utility implementations are correct
+
+#### Test Cases:
+1. **Auth Utilities (`app/utils/auth.py`)**
+   - Verify all functions defined
+   - Verify function signatures
+   - Check for missing implementations
+
+2. **Database Utilities (`app/utils/database.py`)**
+   - Verify all functions defined
+   - Verify function signatures
+   - Check for missing implementations
+
+3. **Error Handlers (`app/utils/errors.py`)**
+   - Verify all exception classes defined
+   - Verify error codes
+   - Check for missing exceptions
+
+4. **Constants (`app/utils/constants.py`)**
+   - Verify all constants defined
+   - Verify constant values
+   - Check for missing constants
+
+5. **Utility Consistency**
+   - Verify all utilities imported where needed
+   - Verify function calls match implementations
+   - Check for missing imports
+
+**Verification:** All utilities compile without errors, functions are properly implemented, no missing imports.
+
+---
+
+### Phase 7: Configuration & Environment Tests
+**Scope:** Settings, environment variables, configuration
+**Sub-agent Task:** Verify all configuration is correct
+
+#### Test Cases:
+1. **Settings (`app/core/settings.py`)**
+   - Verify all settings defined
+   - Verify default values
+   - Check for missing settings
+
+2. **Database Configuration (`app/core/database.py`)**
+   - Verify database URL configuration
+   - Verify async/sync engine setup
+   - Check for missing configuration
+
+3. **App Configuration (`app/main.py`)**
+   - Verify FastAPI app initialization
+   - Verify middleware setup
+   - Verify CORS configuration
+   - Check for missing configuration
+
+4. **Environment Consistency**
+   - Verify all settings used in code
+   - Verify environment variables match settings
+   - Check for missing configuration
+
+**Verification:** All configuration compiles without errors, settings are properly defined, no missing configuration.
+
+---
+
+### Phase 8: Integration Tests
+**Scope:** Cross-component integration, API consistency
+**Sub-agent Task:** Verify all components work together correctly
+
+#### Test Cases:
+1. **Router-Service Integration**
+   - Verify routers call correct service functions
+   - Verify service functions return correct types
+   - Check for integration issues
+
+2. **Service-Model Integration**
+   - Verify services use correct models
+   - Verify model operations are correct
+   - Check for integration issues
+
+3. **Schema-Router Integration**
+   - Verify routers use correct schemas
+   - Verify schemas match request/response
+   - Check for integration issues
+
+4. **Database-Model Integration**
+   - Verify models match database schema
+   - Verify migrations create correct tables
+   - Check for integration issues
+
+5. **Overall Consistency**
+   - Verify all imports are correct
+   - Verify all function calls are valid
+   - Check for circular dependencies
+   - Verify no orphaned code
+
+**Verification:** All components integrate correctly, no circular dependencies, all imports valid.
+
+---
+
+## Execution Strategy
+
+### Sub-Agent Execution Order:
+1. **Phase 1:** Database & Migration Tests
+2. **Phase 2:** Model Layer Tests
+3. **Phase 3:** Schema Layer Tests
+4. **Phase 4:** Router Layer Tests
+5. **Phase 5:** Service Layer Tests
+6. **Phase 6:** Utility & Helper Tests
+7. **Phase 7:** Configuration & Environment Tests
+8. **Phase 8:** Integration Tests
+
+### Context Management:
+- Each sub-agent handles one phase at a time
+- Sub-agents return only findings and issues
+- Main agent aggregates results and coordinates fixes
+- Maximum context usage per sub-agent: ~50,000 tokens
+
+### Verification Criteria:
+- All files compile without syntax errors
+- All imports resolve correctly
+- All function signatures match across components
+- All foreign keys reference existing tables
+- All schemas have proper validation
+- All routers have proper dependencies
+- No circular dependencies
+- No orphaned code
+
+### Issue Reporting:
+Each sub-agent should report:
+1. **Critical Issues:** Missing files, broken imports, syntax errors
+2. **Consistency Issues:** Mismatched types, missing fields, incorrect references
+3. **Recommendations:** Improvements, missing features, best practices
+
+---
+
+## Summary
+
+This test plan provides a systematic approach to verifying the entire backend system by breaking it down into 8 manageable phases. Each phase can be executed by a sub-agent independently, ensuring comprehensive coverage while staying within context limits. The plan focuses on consistency, correctness, and completeness of the codebase.