Testes das funções do post sobre como documentar seu código.

test_main.py

from main import calculate_simple_interest_investment, calculate_compound_interest_investment


def test_calculate_compound_interest_investment_when_principal_amount_is_zero():
    principal_amount = 0.0
    rate = 0.07
    time = 2
    expected_interest = 0

    interest = calculate_compound_interest_investment(
        principal_amount, rate, time
    )

    assert interest == expected_interest


def test_calculate_compound_interest_investment_when_rate_is_zero():
    principal_amount = 1400
    rate = 0.0
    time = 2
    expected_interest = 1400.0

    interest = calculate_compound_interest_investment(
        principal_amount, rate, time
    )

    assert interest == expected_interest


def test_calculate_compound_interest_investment_when_time_is_zero():
    principal_amount = 1400
    rate = 0.07
    time = 0
    expected_interest = 1400.0

    interest = calculate_compound_interest_investment(
        principal_amount, rate, time
    )

    assert interest == expected_interest


def test_calculate_compound_interest_investment_when_all_parameters_are_not_zero():
    principal_amount = 1400
    rate = 0.07
    time = 2
    expected_interest = 1602.86

    interest = round(calculate_compound_interest_investment(
        principal_amount, rate, time
    ), 2)

    assert interest == expected_interest


def test_calculate_simple_interest_investment_when_principal_amount_is_zero():
    principal_amount = 0.0
    rate = 0.02
    time = 15
    expected_interest = 0

    interest = calculate_simple_interest_investment(
        principal_amount, rate, time
    )

    assert interest == expected_interest


def test_calculate_simple_interest_investment_when_rate_is_zero():
    principal_amount = 1200
    rate = 0.0
    time = 15
    expected_interest = 1200.0

    interest = calculate_simple_interest_investment(
        principal_amount, rate, time
    )

    assert interest == expected_interest


def test_calculate_simple_interest_investment_when_time_is_zero():
    principal_amount = 1200
    rate = 0.02
    time = 0
    expected_interest = 1200.0

    interest = calculate_simple_interest_investment(
        principal_amount, rate, time
    )

    assert interest == expected_interest


def test_calculate_simple_interest_investment_when_all_parameters_are_not_zero():
    principal_amount = 1200
    rate = 0.02
    time = 15
    expected_interest = 1560.0

    interest = calculate_simple_interest_investment(
        principal_amount, rate, time
    )

    assert interest == expected_interest