test: add repository factory and CLI db-reset tests

- test_factory.py: verify database factory selects correct backend
- test_cli_db_reset.py: test CLI database reset functionality

tests/test_cli_db_reset.py

@@ -0,0 +1,134 @@
+"""
+Tests for the `decnet db-reset` CLI command.
+
+No live MySQL required — the async worker is mocked.
+"""
+from unittest.mock import AsyncMock, patch
+
+import pytest
+from typer.testing import CliRunner
+
+from decnet.cli import app, _db_reset_mysql_async
+
+
+runner = CliRunner()
+
+
+# ── Guard-rails ───────────────────────────────────────────────────────────────
+
+class TestDbResetGuards:
+    def test_refuses_when_backend_is_sqlite(self, monkeypatch):
+        monkeypatch.setenv("DECNET_DB_TYPE", "sqlite")
+        result = runner.invoke(app, ["db-reset", "--i-know-what-im-doing"])
+        assert result.exit_code == 2
+        assert "MySQL-only" in result.stdout
+
+    def test_refuses_invalid_mode(self, monkeypatch):
+        monkeypatch.setenv("DECNET_DB_TYPE", "mysql")
+        result = runner.invoke(app, ["db-reset", "--mode", "nuke"])
+        assert result.exit_code == 2
+        assert "Invalid --mode" in result.stdout
+
+    def test_reports_missing_connection_info(self, monkeypatch):
+        """With no URL and no component env vars, build_mysql_url raises — surface it."""
+        monkeypatch.setenv("DECNET_DB_TYPE", "mysql")
+        for v in ("DECNET_DB_URL", "DECNET_DB_PASSWORD"):
+            monkeypatch.delenv(v, raising=False)
+        # Strip pytest env so build_mysql_url's safety check trips (needs a
+        # password when we're "not in tests" per its own heuristic).
+        import os
+        for k in list(os.environ):
+            if k.startswith("PYTEST"):
+                monkeypatch.delenv(k, raising=False)
+
+        result = runner.invoke(app, ["db-reset"])
+        assert result.exit_code == 2
+        assert "DECNET_DB_PASSWORD" in result.stdout
+
+
+# ── Dry-run vs. confirmed execution ───────────────────────────────────────────
+
+class TestDbResetDispatch:
+    def test_dry_run_skips_destructive_phase(self, monkeypatch):
+        """Without the flag, the command must still call into the worker
+        (to show row counts) but signal confirm=False."""
+        monkeypatch.setenv("DECNET_DB_TYPE", "mysql")
+        monkeypatch.setenv("DECNET_DB_URL", "mysql+aiomysql://u:p@h/d")
+
+        mock = AsyncMock()
+        with patch("decnet.cli._db_reset_mysql_async", new=mock):
+            result = runner.invoke(app, ["db-reset"])
+
+        assert result.exit_code == 0, result.stdout
+        mock.assert_awaited_once()
+        kwargs = mock.await_args.kwargs
+        assert kwargs["confirm"] is False
+        assert kwargs["mode"] == "truncate"
+
+    def test_confirmed_execution_passes_confirm_true(self, monkeypatch):
+        monkeypatch.setenv("DECNET_DB_TYPE", "mysql")
+        monkeypatch.setenv("DECNET_DB_URL", "mysql+aiomysql://u:p@h/d")
+
+        mock = AsyncMock()
+        with patch("decnet.cli._db_reset_mysql_async", new=mock):
+            result = runner.invoke(app, ["db-reset", "--i-know-what-im-doing"])
+
+        assert result.exit_code == 0, result.stdout
+        assert mock.await_args.kwargs["confirm"] is True
+
+    def test_drop_tables_mode_propagates(self, monkeypatch):
+        monkeypatch.setenv("DECNET_DB_TYPE", "mysql")
+        monkeypatch.setenv("DECNET_DB_URL", "mysql+aiomysql://u:p@h/d")
+
+        mock = AsyncMock()
+        with patch("decnet.cli._db_reset_mysql_async", new=mock):
+            result = runner.invoke(
+                app, ["db-reset", "--mode", "drop-tables", "--i-know-what-im-doing"]
+            )
+
+        assert result.exit_code == 0, result.stdout
+        assert mock.await_args.kwargs["mode"] == "drop-tables"
+
+    def test_explicit_url_overrides_env(self, monkeypatch):
+        monkeypatch.setenv("DECNET_DB_TYPE", "mysql")
+        monkeypatch.setenv("DECNET_DB_URL", "mysql+aiomysql://from-env/db")
+
+        mock = AsyncMock()
+        with patch("decnet.cli._db_reset_mysql_async", new=mock):
+            result = runner.invoke(app, [
+                "db-reset", "--url", "mysql+aiomysql://override/db2",
+            ])
+
+        assert result.exit_code == 0, result.stdout
+        # First positional arg to the async worker is the DSN.
+        assert mock.await_args.args[0] == "mysql+aiomysql://override/db2"
+
+
+# ── Destructive-phase skip when flag is absent ───────────────────────────────
+
+class TestDbResetWorker:
+    @pytest.mark.anyio
+    async def test_dry_run_does_not_open_begin_transaction(self):
+        """Confirm=False must stop after the row-count inspection — no DDL/DML."""
+        from unittest.mock import MagicMock
+
+        mock_conn = AsyncMock()
+        # Every table shows as "missing" so row-count loop exits cleanly.
+        mock_conn.execute.side_effect = Exception("no such table")
+
+        mock_connect_cm = AsyncMock()
+        mock_connect_cm.__aenter__.return_value = mock_conn
+        mock_connect_cm.__aexit__.return_value = False
+
+        mock_engine = MagicMock()
+        mock_engine.connect.return_value = mock_connect_cm
+        mock_engine.begin = MagicMock()  # must NOT be awaited in dry-run
+        mock_engine.dispose = AsyncMock()
+
+        with patch("sqlalchemy.ext.asyncio.create_async_engine", return_value=mock_engine):
+            await _db_reset_mysql_async(
+                "mysql+aiomysql://u:p@h/d", mode="truncate", confirm=False
+            )
+
+        mock_engine.begin.assert_not_called()
+        mock_engine.dispose.assert_awaited_once()

tests/test_factory.py

@@ -0,0 +1,44 @@
+"""
+Unit tests for the repository factory — dispatch on DECNET_DB_TYPE.
+"""
+import pytest
+
+from decnet.web.db.factory import get_repository
+from decnet.web.db.sqlite.repository import SQLiteRepository
+from decnet.web.db.mysql.repository import MySQLRepository
+
+
+def test_factory_defaults_to_sqlite(monkeypatch, tmp_path):
+    monkeypatch.delenv("DECNET_DB_TYPE", raising=False)
+    repo = get_repository(db_path=str(tmp_path / "t.db"))
+    assert isinstance(repo, SQLiteRepository)
+
+
+def test_factory_sqlite_explicit(monkeypatch, tmp_path):
+    monkeypatch.setenv("DECNET_DB_TYPE", "sqlite")
+    repo = get_repository(db_path=str(tmp_path / "t.db"))
+    assert isinstance(repo, SQLiteRepository)
+
+
+def test_factory_mysql_branch(monkeypatch):
+    """MySQL branch must import and instantiate without a live server.
+
+    Engine creation is lazy in SQLAlchemy — no socket is opened until the
+    first query — so the repository constructs cleanly here.
+    """
+    monkeypatch.setenv("DECNET_DB_TYPE", "mysql")
+    monkeypatch.setenv("DECNET_DB_URL", "mysql+aiomysql://u:p@127.0.0.1:3306/x")
+    repo = get_repository()
+    assert isinstance(repo, MySQLRepository)
+
+
+def test_factory_is_case_insensitive(monkeypatch, tmp_path):
+    monkeypatch.setenv("DECNET_DB_TYPE", "SQLite")
+    repo = get_repository(db_path=str(tmp_path / "t.db"))
+    assert isinstance(repo, SQLiteRepository)
+
+
+def test_factory_rejects_unknown_type(monkeypatch):
+    monkeypatch.setenv("DECNET_DB_TYPE", "cassandra")
+    with pytest.raises(ValueError, match="Unsupported database type"):
+        get_repository()