tests/test_credit_service.py

"""
Comprehensive Tests for Credit Service

Tests cover:
1. Credit Manager - reserve, confirm, refund operations
2. Error pattern matching - refundable vs non-refundable
3. Job completion handling
4. Credits Router endpoints
5. Credit middleware (if needed)

Uses mocked database and user models.
"""
import pytest
from datetime import datetime
from unittest.mock import patch, MagicMock, AsyncMock
from fastapi.testclient import TestClient


# ============================================================================
# 1. Credit Manager Tests
# ============================================================================

class TestCreditReservation:
    """Test credit reservation functionality."""
    
    @pytest.mark.asyncio
    async def test_reserve_credit_success(self):
        """Successfully reserve credits from user balance."""
        from services.credit_service.credit_manager import reserve_credit
        
        # Mock user with sufficient credits
        mock_user = MagicMock()
        mock_user.user_id = "usr_123"
        mock_user.credits = 10
        
        mock_session = AsyncMock()
        
        result = await reserve_credit(mock_session, mock_user, amount=5)
        
        assert result == True
        assert mock_user.credits == 5  # 10 - 5
    
    @pytest.mark.asyncio
    async def test_reserve_credit_insufficient(self):
        """Cannot reserve more credits than user has."""
        from services.credit_service.credit_manager import reserve_credit
        
        mock_user = MagicMock()
        mock_user.user_id = "usr_123"
        mock_user.credits = 3
        
        mock_session = AsyncMock()
        
        result = await reserve_credit(mock_session, mock_user, amount=5)
        
        assert result == False
        assert mock_user.credits == 3  # Unchanged
    
    @pytest.mark.asyncio
    async def test_reserve_credit_exact_amount(self):
        """Can reserve exact balance."""
        from services.credit_service.credit_manager import reserve_credit
        
        mock_user = MagicMock()
        mock_user.credits = 10
        
        mock_session = AsyncMock()
        
        result = await reserve_credit(mock_session, mock_user, amount=10)
        
        assert result == True
        assert mock_user.credits == 0


class TestCreditConfirmation:
    """Test credit confirmation on job completion."""
    
    @pytest.mark.asyncio
    async def test_confirm_credit_clears_reservation(self):
        """Confirming credit clears the reservation tracking."""
        from services.credit_service.credit_manager import confirm_credit
        
        mock_job = MagicMock()
        mock_job.job_id = "job_123"
        mock_job.credits_reserved = 5
        
        mock_session = AsyncMock()
        
        await confirm_credit(mock_session, mock_job)
        
        assert mock_job.credits_reserved == 0
    
    @pytest.mark.asyncio
    async def test_confirm_credit_no_reservation(self):
        """Confirming when no credits reserved does nothing."""
        from services.credit_service.credit_manager import confirm_credit
        
        mock_job = MagicMock()
        mock_job.credits_reserved = 0
        
        mock_session = AsyncMock()
        
        await confirm_credit(mock_session, mock_job)
        
        assert mock_job.credits_reserved == 0


class TestCreditRefund:
    """Test credit refund functionality."""
    
    @pytest.mark.asyncio
    async def test_refund_credit_success(self):
        """Successfully refund credits to user."""
        from services.credit_service.credit_manager import refund_credit
        from core.models import User
        
        # Mock job with reserved credits
        mock_job = MagicMock()
        mock_job.job_id = "job_123"
        mock_job.user_id = 1
        mock_job.credits_reserved = 5
        mock_job.credits_refunded = False
        
        # Mock user
        mock_user = MagicMock(spec=User)
        mock_user.id = 1
        mock_user.user_id = "usr_123"
        mock_user.credits = 10
        
        # Mock database session
        mock_session = AsyncMock()
        mock_result = MagicMock()
        mock_result.scalar_one_or_none.return_value = mock_user
        mock_session.execute.return_value = mock_result
        
        result = await refund_credit(mock_session, mock_job, "Test refund")
        
        assert result == True
        assert mock_user.credits == 15  # 10 + 5
        assert mock_job.credits_reserved == 0
        assert mock_job.credits_refunded == True
    
    @pytest.mark.asyncio
    async def test_refund_credit_no_reservation(self):
        """Cannot refund if no credits were reserved."""
        from services.credit_service.credit_manager import refund_credit
        
        mock_job = MagicMock()
        mock_job.credits_reserved = 0
        
        mock_session = AsyncMock()
        
        result = await refund_credit(mock_session, mock_job, "Test")
        
        assert result == False
    
    @pytest.mark.asyncio
    async def test_refund_credit_already_refunded(self):
        """Cannot refund credits twice."""
        from services.credit_service.credit_manager import refund_credit
        
        mock_job = MagicMock()
        mock_job.credits_reserved = 5
        mock_job.credits_refunded = True
        
        mock_session = AsyncMock()
        
        result = await refund_credit(mock_session, mock_job, "Test")
        
        assert result == False


# ============================================================================
# 2. Error Pattern Matching Tests
# ============================================================================

class TestErrorPatternMatching:
    """Test refundable vs non-refundable error detection."""
    
    def test_refundable_api_key_error(self):
        """API key errors are refundable."""
        from services.credit_service.credit_manager import is_refundable_error
        
        assert is_refundable_error("API_KEY_INVALID: The API key is invalid") == True
    
    def test_refundable_quota_exceeded(self):
        """Quota exceeded is refundable."""
        from services.credit_service.credit_manager import is_refundable_error
        
        assert is_refundable_error("QUOTA_EXCEEDED: Daily quota exceeded") == True
    
    def test_refundable_internal_error(self):
        """Internal server errors are refundable."""
        from services.credit_service.credit_manager import is_refundable_error
        
        assert is_refundable_error("INTERNAL_ERROR: Something went wrong") == True
    
    def test_refundable_timeout(self):
        """Timeouts are refundable."""
        from services.credit_service.credit_manager import is_refundable_error
        
        assert is_refundable_error("Request TIMEOUT after 30 seconds") == True
    
    def test_refundable_500_error(self):
        """HTTP 500 errors are refundable."""
        from services.credit_service.credit_manager import is_refundable_error
        
        assert is_refundable_error("Server returned 500 Internal Server Error") == True
    
    def test_non_refundable_safety_filter(self):
        """Safety filter blocks are not refundable."""
        from services.credit_service.credit_manager import is_refundable_error
        
        assert is_refundable_error("Content blocked by safety filter") == False
    
    def test_non_refundable_invalid_input(self):
        """Invalid input errors are not refundable."""
        from services.credit_service.credit_manager import is_refundable_error
        
        assert is_refundable_error("INVALID_INPUT: Bad image format") == False
    
    def test_non_refundable_400_error(self):
        """HTTP 400 errors are not refundable."""
        from services.credit_service.credit_manager import is_refundable_error
        
        assert is_refundable_error("Bad request: 400 status code") == False
    
    def test_non_refundable_cancelled(self):
        """User cancellations are not refundable."""
        from services.credit_service.credit_manager import is_refundable_error
        
        assert is_refundable_error("User cancelled the operation") == False
    
    def test_refundable_max_retries(self):
        """Max retries exceeded is refundable."""
        from services.credit_service.credit_manager import is_refundable_error
        
        assert is_refundable_error("Failed after max retries") == True
    
    def test_unknown_error_not_refundable(self):
        """Unknown errors default to non-refundable."""
        from services.credit_service.credit_manager import is_refundable_error
        
        assert is_refundable_error("Some random unknown error") == False
    
    def test_empty_error_not_refundable(self):
        """Empty error message is not refundable."""
        from services.credit_service.credit_manager import is_refundable_error
        
        assert is_refundable_error("") == False
        assert is_refundable_error(None) == False


# ============================================================================
# 3. Job Completion Handling Tests
# ============================================================================

class TestJobCompletionHandling:
    """Test credit handling when jobs complete."""
    
    @pytest.mark.asyncio
    async def test_completed_job_confirms_credits(self):
        """Completed jobs confirm credit usage."""
        from services.credit_service.credit_manager import handle_job_completion
        
        mock_job = MagicMock()
        mock_job.job_id = "job_123"
        mock_job.status = "completed"
        mock_job.credits_reserved = 5
        
        mock_session = AsyncMock()
        
        with patch('services.credit_service.credit_manager.confirm_credit') as mock_confirm:
            await handle_job_completion(mock_session, mock_job)
            mock_confirm.assert_called_once()
    
    @pytest.mark.asyncio
    async def test_failed_refundable_job_refunds(self):
        """Failed jobs with refundable errors get refunds."""
        from services.credit_service.credit_manager import handle_job_completion
        
        mock_job = MagicMock()
        mock_job.status = "failed"
        mock_job.error_message = "API_KEY_INVALID: Bad key"
        mock_job.credits_reserved = 5
        
        mock_session = AsyncMock()
        
        with patch('services.credit_service.credit_manager.refund_credit') as mock_refund:
            await handle_job_completion(mock_session, mock_job)
            mock_refund.assert_called_once()
    
    @pytest.mark.asyncio
    async def test_failed_non_refundable_job_keeps_credits(self):
        """Failed jobs with non-refundable errors keep credits."""
        from services.credit_service.credit_manager import handle_job_completion
        
        mock_job = MagicMock()
        mock_job.status = "failed"
        mock_job.error_message = "Safety filter blocked content"
        mock_job.credits_reserved = 5
        
        mock_session = AsyncMock()
        
        with patch('services.credit_service.credit_manager.confirm_credit') as mock_confirm:
            await handle_job_completion(mock_session, mock_job)
            mock_confirm.assert_called_once()
    
    @pytest.mark.asyncio
    async def test_cancelled_before_start_refunds(self):
        """Cancelled jobs that never started get refunds."""
        from services.credit_service.credit_manager import handle_job_completion
        
        mock_job = MagicMock()
        mock_job.status = "cancelled"
        mock_job.started_at = None
        mock_job.credits_reserved = 5
        
        mock_session = AsyncMock()
        
        with patch('services.credit_service.credit_manager.refund_credit') as mock_refund:
            await handle_job_completion(mock_session, mock_job)
            mock_refund.assert_called_once()
    
    @pytest.mark.asyncio
    async def test_cancelled_during_processing_keeps_credits(self):
        """Cancelled jobs that started keep credits."""
        from services.credit_service.credit_manager import handle_job_completion
        
        mock_job = MagicMock()
        mock_job.status = "cancelled"
        mock_job.started_at = datetime.utcnow()
        mock_job.credits_reserved = 5
        
        mock_session = AsyncMock()
        
        with patch('services.credit_service.credit_manager.confirm_credit') as mock_confirm:
            await handle_job_completion(mock_session, mock_job)
            mock_confirm.assert_called_once()


# ============================================================================
# 4. Credits Router Tests
# ============================================================================

class TestCreditsRouter:
    """Test credits API endpoints."""
    
    def test_get_balance_requires_auth(self):
        """GET /credits/balance requires authentication."""
        from routers.credits import router
        from fastapi import FastAPI
        
        app = FastAPI()
        app.include_router(router)
        client = TestClient(app)
        
        response = client.get("/credits/balance")
        
        # Should fail without auth
        assert response.status_code == 500  # Attribute Error - no middleware
    
    def test_get_balance_returns_user_credits(self):
        """GET /credits/balance returns user's credit balance."""
        from routers.credits import router
        from fastapi import FastAPI
        
        app = FastAPI()
        
        # Mock authenticated user in request state
        mock_user = MagicMock()
        mock_user.user_id = "usr_123"
        mock_user.credits = 50
        mock_user.last_used_at = None
        
        # Create test client with middleware that sets request.state.user
        @app.middleware("http")
        async def add_user_to_state(request, call_next):
            request.state.user = mock_user
            return await call_next(request)
        
        app.include_router(router)
        client = TestClient(app)
        
        response = client.get("/credits/balance")
        
        assert response.status_code == 200
        data = response.json()
        assert data["user_id"] == "usr_123"
        assert data["credits"] == 50
    
    def test_get_history_requires_auth(self):
        """GET /credits/history requires authentication."""
        from routers.credits import router
        from fastapi import FastAPI
        
        app = FastAPI()
        app.include_router(router)
        client = TestClient(app)
        
        response = client.get("/credits/history")
        
        # Should fail without auth
        assert response.status_code == 500  # Attribute Error - no middleware
    
    def test_get_history_returns_paginated_jobs(self):
        """GET /credits/history returns paginated job list."""
        from routers.credits import router
        from fastapi import FastAPI
        from core.database import get_db
        
        app = FastAPI()
        
        mock_user = MagicMock()
        mock_user.user_id = "usr_123"
        mock_user.credits = 50
        
        # Mock database with jobs
        mock_job = MagicMock()
        mock_job.job_id = "job_123"
        mock_job.job_type = "generate-video"
        mock_job.status = "completed"
        mock_job.credits_reserved = 10
        mock_job.credits_refunded = False
        mock_job.error_message = None
        mock_job.created_at = datetime.utcnow()
        mock_job.completed_at = datetime.utcnow()
        
        async def mock_get_db():
            mock_db = AsyncMock()
            mock_result = MagicMock()
            mock_result.scalars.return_value.all.return_value = [mock_job]
            mock_db.execute.return_value = mock_result
            yield mock_db
        
        @app.middleware("http")
        async def add_user_to_state(request, call_next):
            request.state.user = mock_user
            return await call_next(request)
        
        app.dependency_overrides[get_db] = mock_get_db
        app.include_router(router)
        client = TestClient(app)
        
        response = client.get("/credits/history")
        
        assert response.status_code == 200
        data = response.json()
        assert data["user_id"] == "usr_123"
        assert data["current_balance"] == 50
        assert len(data["history"]) == 1
        assert data["history"][0]["job_id"] == "job_123"
    
    def test_get_history_pagination(self):
        """GET /credits/history supports pagination."""
        from routers.credits import router
        from fastapi import FastAPI
        from core.database import get_db
        
        app = FastAPI()
        
        mock_user = MagicMock()
        mock_user.user_id = "usr_123"
        mock_user.credits = 50
        
        async def mock_get_db():
            mock_db = AsyncMock()
            mock_result = MagicMock()
            mock_result.scalars.return_value.all.return_value = []
            mock_db.execute.return_value = mock_result
            yield mock_db
        
        @app.middleware("http")
        async def add_user_to_state(request, call_next):
            request.state.user = mock_user
            return await call_next(request)
        
        app.dependency_overrides[get_db] = mock_get_db
        app.include_router(router)
        client = TestClient(app)
        
        response = client.get("/credits/history?page=2&limit=10")
        
        assert response.status_code == 200
        data = response.json()
        assert data["page"] == 2
        assert data["limit"] == 10


if __name__ == "__main__":
    pytest.main([__file__, "-v"])