Approximate comparisons (pytest.approx) - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to assert that 0.1 + 0.2 is approximately equal to 0.3 using pytest.approx.

PyTest

import pytest

def test_sum():
    assert 0.1 + 0.2 == [1]

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Apytest.approx(0.3)

B0.3

Capprox(0.3)

D0.30000000000000004

Attempts:

3 left

💡 Hint

Common Mistakes

Using direct equality (==) with floating points causes test failures due to precision errors.

Using a plain float instead of pytest.approx for approximate comparison.

pytest.approx allows approximate comparison of floating point numbers, handling small rounding errors.

2fill in blank

medium

Complete the code to assert that the list [1.0, 2.0, 3.0] is approximately equal to [1.0, 2.0001, 3.0] using pytest.approx.

PyTest

import pytest

def test_list_approx():
    result = [1.0, 2.0, 3.0]
    expected = [1.0, 2.0001, 3.0]
    assert result == [1]

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Apytest.approx(expected)

Bexpected

Capprox(expected)

Dexpected.approx()

Attempts:

3 left

💡 Hint

Common Mistakes

Comparing lists directly without pytest.approx causes failures due to small differences.

Trying to call approx() without importing pytest.

pytest.approx works with lists to compare each element approximately.

3fill in blank

hard

Fix the error in the test by completing the code to compare floating point numbers approximately with a relative tolerance of 1e-3.

PyTest

import pytest

def test_relative_tolerance():
    value = 100.0
    expected = 100.1
    assert value == pytest.approx(expected, [1]=1e-3)

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Aabs

Brelative

Crel

Drel_tol

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'abs' instead of 'rel' for relative tolerance.

Using 'rel_tol' or 'relative' which are not valid pytest.approx parameters.

The correct keyword argument for relative tolerance in pytest.approx is rel.

4fill in blank

hard

Fill both blanks to assert that 0.123456 is approximately equal to 0.123 with an absolute tolerance of 1e-3.

PyTest

import pytest

def test_absolute_tolerance():
    assert 0.123456 == pytest.approx(0.123, [1]=[2])

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Aabs

Brel

C1e-3

D1e-4

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'rel' instead of 'abs' for absolute tolerance.

Setting tolerance too small to allow the difference.

Use abs for absolute tolerance and set it to 1e-3 to allow small absolute differences.

5fill in blank

hard

Fill all three blanks to assert that the dictionary {'a': 1.0, 'b': 2.0} is approximately equal to {'a': 1.001, 'b': 2.002} with relative tolerance 1e-2 and absolute tolerance 1e-4.

PyTest

import pytest

def test_dict_approx():
    result = {'a': 1.0, 'b': 2.0}
    expected = {'a': 1.001, 'b': 2.002}
    assert result == pytest.approx(expected, [1]=[2], [3]=[4])

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Arel

Babs

C1e-2

D1e-4

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping 'rel' and 'abs' keywords.

Using incorrect tolerance values causing test failures.

pytest.approx accepts both rel for relative tolerance and abs for absolute tolerance. Here, rel=1e-2 and abs=1e-4 allow approximate comparison of dictionary values.