tests/test_core.py

# Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0
# For details: https://github.com/nedbat/coveragepy/blob/master/NOTICE.txt

"""Tests for core selection of coverage.py."""

from __future__ import annotations

import pytest

import coverage
from coverage import env
from coverage.exceptions import ConfigError

from tests.coveragetest import CoverageTest
from tests.helpers import re_line, re_lines


class CoverageCoreTest(CoverageTest):
    """Test that cores are chosen correctly."""

    # This doesn't test failure modes, only successful requests.
    try:
        from coverage.tracer import CTracer

        has_ctracer = True
    except ImportError:
        has_ctracer = False

    def setUp(self) -> None:
        super().setUp()
        # Clean out the environment variable the test suite uses to control the
        # core it cares about.
        self.del_environ("COVERAGE_CORE")
        self.make_file("numbers.py", "print(123, 456)")

    def test_core_default(self) -> None:
        out = self.run_command("coverage run --debug=sys numbers.py")
        assert out.endswith("123 456\n")
        core = re_line(r" core:", out).strip()
        warns = re_lines(r"\(no-ctracer\)", out)
        if env.SYSMON_DEFAULT:
            assert core == "core: SysMonitor"
            assert not warns
        elif self.has_ctracer:
            assert core == "core: CTracer"
            assert not warns
        else:
            assert core == "core: PyTracer"
            assert bool(warns) == env.CPYTHON

    @pytest.mark.skipif(not has_ctracer, reason="No CTracer to request")
    def test_core_request_ctrace(self) -> None:
        self.set_environ("COVERAGE_CORE", "ctrace")
        out = self.run_command("coverage run --debug=sys numbers.py")
        assert out.endswith("123 456\n")
        core = re_line(r" core:", out).strip()
        assert core == "core: CTracer"

    @pytest.mark.skipif(has_ctracer, reason="CTracer needs to be missing")
    def test_core_request_ctrace_but_missing(self) -> None:
        self.make_file(".coveragerc", "[run]\ncore = ctrace\n")
        out = self.run_command("coverage run --debug=sys,pybehave numbers.py")
        assert out.endswith("123 456\n")
        core = re_line(r" core:", out).strip()
        assert core == "core: PyTracer"
        warns = re_lines(r"\(no-ctracer\)", out)
        assert bool(warns) == env.SHIPPING_WHEELS

    def test_core_request_pytrace(self) -> None:
        self.set_environ("COVERAGE_CORE", "pytrace")
        out = self.run_command("coverage run --debug=sys numbers.py")
        assert out.endswith("123 456\n")
        core = re_line(r" core:", out).strip()
        assert core == "core: PyTracer"

    def test_core_request_sysmon(self) -> None:
        self.set_environ("COVERAGE_CORE", "sysmon")
        out = self.run_command("coverage run --debug=sys numbers.py")
        assert out.endswith("123 456\n")
        core = re_line(r" core:", out).strip()
        warns = re_lines(r"\(no-sysmon\)", out)
        if env.PYBEHAVIOR.pep669:
            assert core == "core: SysMonitor"
            assert not warns
        else:
            assert core in ["core: CTracer", "core: PyTracer"]
            assert warns

    def test_core_request_sysmon_no_dyncontext(self) -> None:
        # Use config core= for this test just to be different.
        self.make_file(
            ".coveragerc",
            """\
            [run]
            core = sysmon
            dynamic_context = test_function
            """,
        )
        out = self.run_command("coverage run --debug=sys numbers.py")
        assert out.endswith("123 456\n")
        core = re_line(r" core:", out).strip()
        assert core in ["core: CTracer", "core: PyTracer"]
        warns = re_lines(r"\(no-sysmon\)", out)
        assert len(warns) == 1
        if env.PYBEHAVIOR.pep669:
            assert (
                "sys.monitoring doesn't yet support dynamic contexts, using default core"
                in warns[0]
            )
        else:
            assert "sys.monitoring isn't available in this version, using default core" in warns[0]

    def test_core_request_sysmon_no_branches(self) -> None:
        # Use config core= for this test just to be different.
        self.make_file(
            ".coveragerc",
            """\
            [run]
            core = sysmon
            branch = True
            """,
        )
        out = self.run_command("coverage run --debug=sys numbers.py")
        assert out.endswith("123 456\n")
        core = re_line(r" core:", out).strip()
        warns = re_lines(r"\(no-sysmon\)", out)
        if env.PYBEHAVIOR.branch_right_left:
            assert core == "core: SysMonitor"
            assert not warns
        else:
            assert core in ["core: CTracer", "core: PyTracer"]
            assert len(warns) == 1
            if env.PYBEHAVIOR.pep669:
                assert (
                    "sys.monitoring can't measure branches in this version, using default core"
                    in warns[0]
                )
            else:
                assert (
                    "sys.monitoring isn't available in this version, using default core" in warns[0]
                )

    def test_core_request_nosuchcore(self) -> None:
        # Test the coverage misconfigurations in-process with pytest. Running a
        # subprocess doesn't capture the metacov in the subprocess because
        # coverage is misconfigured.
        self.set_environ("COVERAGE_CORE", "nosuchcore")
        cov = coverage.Coverage()
        with pytest.raises(ConfigError, match=r"Unknown core value: 'nosuchcore'"):
            self.start_import_stop(cov, "numbers")