Harden runtime and add backup foundation

tests/test_database.py

@@ -0,0 +1,49 @@
+"""Tests for SQLite connection pragmas and runtime behavior."""
+
+import sqlite3
+
+import atocore.config as config
+from atocore.models.database import get_connection, init_db
+
+
+def test_get_connection_applies_busy_timeout_and_wal(tmp_path, monkeypatch):
+    monkeypatch.setenv("ATOCORE_DATA_DIR", str(tmp_path / "data"))
+    monkeypatch.setenv("ATOCORE_DB_BUSY_TIMEOUT_MS", "7000")
+
+    original_settings = config.settings
+    try:
+        config.settings = config.Settings()
+        init_db()
+        with get_connection() as conn:
+            busy_timeout = conn.execute("PRAGMA busy_timeout").fetchone()[0]
+            journal_mode = conn.execute("PRAGMA journal_mode").fetchone()[0]
+            foreign_keys = conn.execute("PRAGMA foreign_keys").fetchone()[0]
+    finally:
+        config.settings = original_settings
+
+    assert busy_timeout == 7000
+    assert str(journal_mode).lower() == "wal"
+    assert foreign_keys == 1
+
+
+def test_get_connection_uses_configured_timeout_value(tmp_path, monkeypatch):
+    monkeypatch.setenv("ATOCORE_DATA_DIR", str(tmp_path / "data"))
+    monkeypatch.setenv("ATOCORE_DB_BUSY_TIMEOUT_MS", "2500")
+
+    original_settings = config.settings
+    original_connect = sqlite3.connect
+    calls = []
+
+    def fake_connect(*args, **kwargs):
+        calls.append(kwargs.get("timeout"))
+        return original_connect(*args, **kwargs)
+
+    try:
+        config.settings = config.Settings()
+        monkeypatch.setattr("atocore.models.database.sqlite3.connect", fake_connect)
+        init_db()
+    finally:
+        config.settings = original_settings
+
+    assert calls
+    assert calls[0] == 2.5