Functions

Approximate comparisons

Use karva.approx() when floating-point results should match within a tolerance. It uses pytest's defaults: relative tolerance 1e-6 and absolute tolerance 1e-12.

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import karva

def test_total():
    assert 0.1 + 0.2 == karva.approx(0.3)

def test_coordinates():
    assert [0.1000001, 0.2] == karva.approx([0.1, 0.2], rel=1e-5)

Mappings, ordered sequences, complex numbers, and Decimal values are supported. Set nan_ok=True to compare NaN values as equal. This is the direct replacement for pytest.approx() when migrating tests:

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# pytest
assert value == pytest.approx(expected)

# Karva
assert value == karva.approx(expected)

Skip

If you want to skip a test when its running, use karva.skip().

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import karva

def test_function():
    karva.skip()

You can optionally provide a reason for skipping the test by passing it as an argument to karva.skip().

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import karva

def test_function():
    karva.skip("This test is not ready yet")

def test_function2():
    karva.skip(reason="This test is not ready yet")

You can still use pytest.skip() to skip tests.

Fail

If you want to fail a test when its running, use karva.fail().

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import karva

def test_function():
    karva.fail()

You can optionally provide a reason for failing the test by passing it as an argument to karva.fail().

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import karva

def test_function():
    karva.fail("This test is not ready yet")

def test_function2():
    karva.fail(reason="This test is not ready yet")

Then running uv run karva test will result in two test fails.

You can still use pytest.fail() to fail tests.

Raises

If you want to assert that a block of code raises a specific exception, use karva.raises().

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import karva

def test_function():
    with karva.raises(ValueError):
        raise ValueError("something went wrong")

You can optionally provide a match parameter to match a regex pattern against the string representation of the exception.

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import karva

def test_function():
    with karva.raises(ValueError, match="something"):
        raise ValueError("something went wrong")

You can access the exception info by using the as keyword. The returned object has type, value, and tb properties.

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import karva

def test_function():
    with karva.raises(ValueError) as exc_info:
        raise ValueError("something went wrong")

    assert exc_info.type is ValueError
    assert str(exc_info.value) == "something went wrong"
    assert exc_info.tb is not None

You can still use pytest.raises() to assert exceptions.