fix(search): 将搜索历史持久化到应用数据库

backend/tests/test_search_history.py

@@ -0,0 +1,22 @@
+from fastapi.testclient import TestClient
+
+from app.main import app
+from app.services import search_history
+
+
+def test_history_survives_new_clients_and_clear():
+    with TestClient(app) as client:
+        for query in ['first', 'second', ' first ']:
+            assert client.post('/api/search', json={'query': query, 'mode': 'fts'}).status_code == 200
+        assert client.get('/api/search/history').json() == {'queries': ['first', 'second']}
+    with TestClient(app) as client:
+        assert client.get('/api/search/history').json() == {'queries': ['first', 'second']}
+        assert client.delete('/api/search/history').json() == {'queries': []}
+    assert search_history.list_queries() == []
+
+
+def test_history_is_bounded_and_blank_queries_are_ignored():
+    for number in range(12):
+        search_history.record(str(number))
+    search_history.record(' ')
+    assert search_history.list_queries() == [str(number) for number in range(11, 1, -1)]