feat: T03 backend core – FastAPI + DB models + Equipment API + Redis cache + health + tests

- FastAPI app with CORS, lifespan handlers
- Pydantic Settings config (DB, Redis, CORS, SMTP, JWT, Rentman)
- SQLAlchemy async engine + session (DeclarativeBase)
- 6 DB models: EquipmentCache, RentalRequest, RentalRequestItem, Contact, AdminUser, SyncLog
- Pydantic schemas: EquipmentItem, EquipmentDetail, PaginatedEquipment, ContactCreate, ContactResponse
- Redis cache helper: set/get/delete_pattern, rate limiting, equipment key builders
- Equipment router: list (search/category/sort/pagination), detail, categories – all cached
- Contact router: POST with Pydantic validation + rate limiting (5/min)
- Health router: GET /api/health with DB + Redis status
- 28 pytest tests (all pass, 90% coverage)
- Dockerfile, requirements.txt, pytest.ini, test_report.md

backend/tests/test_cache.py

@@ -0,0 +1,84 @@
+"""Tests for Redis cache helpers."""
+
+import pytest
+import fakeredis.aioredis
+
+from app.cache import (
+    _cache_client,
+    check_rate_limit,
+    delete_pattern,
+    equipment_categories_key,
+    equipment_detail_key,
+    equipment_list_key,
+    get_cache,
+    get_cached,
+    set_cache,
+)
+
+
+@pytest.mark.asyncio
+async def test_set_and_get_cache(fake_redis):
+    """set_cache stores JSON and get_cached retrieves it."""
+    await set_cache("test:key", {"foo": "bar"}, ttl=60)
+    result = await get_cached("test:key")
+    assert result == {"foo": "bar"}
+
+
+@pytest.mark.asyncio
+async def test_get_cached_miss(fake_redis):
+    """get_cached returns None for non-existent key."""
+    result = await get_cached("nonexistent:key")
+    assert result is None
+
+
+@pytest.mark.asyncio
+async def test_delete_pattern(fake_redis):
+    """delete_pattern removes matching keys."""
+    await set_cache("equipment:list:1:all:default:all", ["a"], ttl=60)
+    await set_cache("equipment:list:2:all:default:all", ["b"], ttl=60)
+    await delete_pattern("equipment:list:*")
+    assert await get_cached("equipment:list:1:all:default:all") is None
+    assert await get_cached("equipment:list:2:all:default:all") is None
+
+
+@pytest.mark.asyncio
+async def test_rate_limit_allows_under_limit(fake_redis):
+    """check_rate_limit allows requests under the limit."""
+    for _ in range(5):
+        allowed = await check_rate_limit("test_ip", max_requests=5, window=60)
+        assert allowed is True
+
+
+@pytest.mark.asyncio
+async def test_rate_limit_blocks_over_limit(fake_redis):
+    """check_rate_limit blocks requests over the limit."""
+    for _ in range(5):
+        await check_rate_limit("blocked_ip", max_requests=5, window=60)
+    allowed = await check_rate_limit("blocked_ip", max_requests=5, window=60)
+    assert allowed is False
+
+
+@pytest.mark.asyncio
+async def test_equipment_list_key(fake_redis):
+    """equipment_list_key builds correct key format."""
+    key = equipment_list_key(1, "Lautsprecher", "name_asc", "K2")
+    assert "equipment" in key
+    assert "list" in key
+    assert "1" in key
+    assert "Lautsprecher" in key
+
+
+@pytest.mark.asyncio
+async def test_equipment_detail_key(fake_redis):
+    """equipment_detail_key builds correct key format."""
+    key = equipment_detail_key(42)
+    assert "equipment" in key
+    assert "detail" in key
+    assert "42" in key
+
+
+@pytest.mark.asyncio
+async def test_equipment_categories_key(fake_redis):
+    """equipment_categories_key builds correct key format."""
+    key = equipment_categories_key()
+    assert key == "equipment:categories"