"""Utility functions to support database interactions in tests."""

from contextlib import contextmanager
import re
from unittest import mock


def mock_db_session(mocker, sql_module):
    """Create a mock database session.

    Also mock the session_scope context manager to use the mock session.

    """
    mock_session = mock.Mock(query=mock.Mock())

    @contextmanager
    def fake_session_manager():
        yield mock_session

    mocker.patch.object(sql_module, 'session_scope', fake_session_manager)

    return mock_session


def remove_repeating_spaces(string):
    """Replace repeating spaces and newline characters with spaces.

    Args:
        string (str): Input string to be processed.

    Returns:
        str: Processed string.

    """
    # Note: would break field values that do have multiple spaces.
    string = re.sub(r'\n+', ' ', string)
    string = re.sub(r' +', ' ', string)
    string = string.strip(' ')
    return string