test_dataset_generator.py

"""
tests/test_dataset_generator.py
--------------------------------
Unit tests for synthetic dataset generator in generate_dataset.py.
"""

import sys
from pathlib import Path

import pandas as pd
import pytest

sys.path.insert(0, str(Path(__file__).resolve().parent.parent))

from generate_dataset import generate_dataset, introduce_errors, make_clean_row, random_date


class TestDatasetGenerator:
    """Test suite for synthetic dataset generation utility."""

    def test_random_date_returns_valid_iso_string(self):
        d_str = random_date()
        assert isinstance(d_str, str)
        parsed_dt = pd.to_datetime(d_str)
        assert parsed_dt.year in [2022, 2023, 2024]

    def test_make_clean_row_structure(self):
        row = make_clean_row(i=42)
        assert isinstance(row, dict)
        assert row["id_venta"] == 42
        assert "precio" in row
        assert "cantidad" in row
        assert "fecha" in row

    def test_generate_dataset_introduces_expected_dirty_data(self):
        df = generate_dataset(n=200)
        assert isinstance(df, pd.DataFrame)
        assert len(df) > 200  # Should include duplicate rows added by introduce_errors
        assert "codigo_venta" in df.columns

        # Verify intentional dirty characteristics
        assert df.isnull().sum().sum() > 0