| """Unit tests for the 5 derived-ratio formulas.""" |
|
|
| from __future__ import annotations |
|
|
| import numpy as np |
| import pandas as pd |
| import pytest |
|
|
| from api.ratios import apply_derived_ratios |
|
|
|
|
| def _row(**overrides) -> pd.DataFrame: |
| base = { |
| "DAYS_EMPLOYED": -637.0, |
| "DAYS_BIRTH": -9461.0, |
| "AMT_INCOME_TOTAL": 200000.0, |
| "AMT_CREDIT": 400000.0, |
| "AMT_ANNUITY": 25000.0, |
| "CNT_FAM_MEMBERS": 2.0, |
| } |
| base.update(overrides) |
| return pd.DataFrame([base]) |
|
|
|
|
| def test_all_five_ratios_present(): |
| out = apply_derived_ratios(_row()) |
| expected = { |
| "DAYS_EMPLOYED_PERC", |
| "INCOME_CREDIT_PERC", |
| "INCOME_PER_PERSON", |
| "ANNUITY_INCOME_PERC", |
| "PAYMENT_RATE", |
| } |
| assert expected.issubset(out.columns) |
|
|
|
|
| def test_known_values(): |
| out = apply_derived_ratios(_row()) |
| row = out.iloc[0] |
| assert row["DAYS_EMPLOYED_PERC"] == pytest.approx(-637.0 / -9461.0) |
| assert row["INCOME_CREDIT_PERC"] == pytest.approx(200000 / 400000) |
| assert row["INCOME_PER_PERSON"] == pytest.approx(200000 / 2) |
| assert row["ANNUITY_INCOME_PERC"] == pytest.approx(25000 / 200000) |
| assert row["PAYMENT_RATE"] == pytest.approx(25000 / 400000) |
|
|
|
|
| def test_division_by_zero_returns_nan(): |
| out = apply_derived_ratios(_row(AMT_CREDIT=0)) |
| row = out.iloc[0] |
| assert pd.isna(row["INCOME_CREDIT_PERC"]) |
| assert pd.isna(row["PAYMENT_RATE"]) |
|
|
|
|
| def test_nan_propagates(): |
| out = apply_derived_ratios(_row(DAYS_EMPLOYED=np.nan)) |
| assert pd.isna(out.iloc[0]["DAYS_EMPLOYED_PERC"]) |
|
|
|
|
| def test_input_dataframe_not_mutated(): |
| df = _row() |
| snapshot = df.copy() |
| _ = apply_derived_ratios(df) |
| pd.testing.assert_frame_equal(df, snapshot) |
|
|
