backend/tests/test_db_sqlite_provider.py

"""
Regression tests for the SQLite provider selection in db_utils.

Guards the fix for the pod crash where ``pysqlite3`` was preferred even though
its build lacked FTS5, causing ``no such module: fts5`` mid-init.
"""

import os
import sqlite3 as stdlib_sqlite3
import sys

import pytest

# Add backend to path
sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

import db_utils


def test_selected_provider_supports_fts5_and_extensions():
    """The provider db_utils actually selected must satisfy both requirements."""
    assert db_utils._probe_fts5(db_utils.sqlite3)
    assert db_utils._probe_loadable_extensions(db_utils.sqlite3)


def test_probe_fts5_true_for_stdlib_when_available():
    # The test environment's stdlib sqlite3 is expected to have FTS5.
    assert db_utils._probe_fts5(stdlib_sqlite3) is True


def test_probe_fts5_false_for_module_without_fts5():
    class _FakeConn:
        def execute(self, _sql):
            raise stdlib_sqlite3.OperationalError("no such module: fts5")

        def close(self):
            pass

    class _FakeModule:
        def connect(self, _target):
            return _FakeConn()

    assert db_utils._probe_fts5(_FakeModule()) is False


def test_probe_loadable_extensions_false_when_attr_missing():
    class _FakeConn:
        # No enable_load_extension attribute.
        def close(self):
            pass

    class _FakeModule:
        def connect(self, _target):
            return _FakeConn()

    assert db_utils._probe_loadable_extensions(_FakeModule()) is False


def test_select_falls_back_to_stdlib_when_pysqlite3_lacks_fts5(monkeypatch):
    """When pysqlite3 lacks FTS5 but stdlib has both, pick stdlib (the pod case)."""

    def fake_probe_fts5(module):
        # Simulate a pysqlite3 build without FTS5.
        if getattr(module, "_is_fake_pysqlite3", False):
            return False
        return module is stdlib_sqlite3

    monkeypatch.setattr(db_utils, "_probe_fts5", fake_probe_fts5)
    monkeypatch.setattr(db_utils, "_probe_loadable_extensions", lambda module: True)

    class _FakePysqlite3:
        _is_fake_pysqlite3 = True

    fake_pysqlite3 = _FakePysqlite3()
    monkeypatch.setitem(sys.modules, "pysqlite3", fake_pysqlite3)

    selected = db_utils._select_sqlite_module()
    assert selected is stdlib_sqlite3


def test_select_raises_actionable_error_when_no_provider_has_fts5(monkeypatch):
    monkeypatch.setattr(db_utils, "_probe_fts5", lambda module: False)
    monkeypatch.setattr(db_utils, "_probe_loadable_extensions", lambda module: True)

    with pytest.raises(RuntimeError) as exc_info:
        db_utils._select_sqlite_module()

    message = str(exc_info.value)
    assert "FTS5" in message
    assert "pysqlite3-binary" in message  # actionable fix is included