Expected failures

@karva.tags.expect_fail treats a failing test as a success and a passing test as a failure.

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import karva

@karva.tags.expect_fail(reason="Waiting for the export fix")
def test_export():
    assert False  # Replace with an assertion for the known bug.

Use @karva.tags.expect_fail or @karva.tags.expect_fail() without a reason. A reason can also be positional: @karva.tags.expect_fail("Known bug"). The reason is retained in JSON, JSONL, and JUnit reports and explains an unexpected pass. Expected failures still show PASS and count as passed in the terminal.

Conditions

Pass boolean conditions to expect failure when any condition is true:

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import sys
import karva

@karva.tags.expect_fail(sys.platform == "win32", reason="Known Windows bug")
def test_export():
    assert False  # Replace with an assertion for the known bug.

@karva.tags.expect_fail(False, False) runs as a normal test.

Restricting the expected exception

Use raises= to require a particular exception or a tuple of exception classes. Subclasses match normally:

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@karva.tags.expect_fail(reason="Known parser bug", raises=ValueError)
def test_invalid_input():
    parse("invalid")

A different exception is a normal failure and follows the retry policy. A matching expected failure is never retried. Without raises=, ordinary test-body exceptions are accepted. Fixture setup and teardown errors, missing fixtures, framework timeouts, background exceptions, and non-None return values cannot become expected failures.

Pytest

@pytest.mark.xfail is also supported:

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import pytest

@pytest.mark.xfail(reason="Known bug")
def test_export():
    assert False  # Replace with an assertion for the known bug.