path: root/tests/test_plugins.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 plugins."""

from __future__ import annotations

import inspect
import io
import math
import os.path

from typing import Any, Dict, List, Optional
from xml.etree import ElementTree

import pytest

import coverage
from coverage import Coverage, env
from coverage.control import Plugins
from coverage.data import line_counts, sorted_lines
from coverage.exceptions import CoverageWarning, NoSource, PluginError
from coverage.misc import import_local_file
from coverage.types import TConfigSectionOut, TLineNo, TPluginConfig

import coverage.plugin

from tests.coveragetest import CoverageTest
from tests.helpers import CheckUniqueFilenames, swallow_warnings


class NullConfig(TPluginConfig):
    """A plugin configure thing when we don't really need one."""
    def get_plugin_options(self, plugin: str) -> TConfigSectionOut:
        return {}


class FakeConfig(TPluginConfig):
    """A fake config for use in tests."""

    def __init__(self, plugin: str, options: Dict[str, Any]) -> None:
        self.plugin = plugin
        self.options = options
        self.asked_for: List[str] = []

    def get_plugin_options(self, plugin: str) -> TConfigSectionOut:
        """Just return the options for `plugin` if this is the right module."""
        self.asked_for.append(plugin)
        if plugin == self.plugin:
            return self.options
        else:
            return {}


class LoadPluginsTest(CoverageTest):
    """Test Plugins.load_plugins directly."""

    def test_implicit_boolean(self) -> None:
        self.make_file("plugin1.py", """\
            from coverage import CoveragePlugin

            class Plugin(CoveragePlugin):
                pass

            def coverage_init(reg, options):
                reg.add_file_tracer(Plugin())
            """)

        config = FakeConfig("plugin1", {})
        plugins = Plugins.load_plugins([], config)
        assert not plugins

        plugins = Plugins.load_plugins(["plugin1"], config)
        assert plugins

    def test_importing_and_configuring(self) -> None:
        self.make_file("plugin1.py", """\
            from coverage import CoveragePlugin

            class Plugin(CoveragePlugin):
                def __init__(self, options):
                    self.options = options
                    self.this_is = "me"

            def coverage_init(reg, options):
                reg.add_file_tracer(Plugin(options))
            """)

        config = FakeConfig("plugin1", {'a': 'hello'})
        plugins = list(Plugins.load_plugins(["plugin1"], config))

        assert len(plugins) == 1
        assert plugins[0].this_is == "me"                   # type: ignore
        assert plugins[0].options == {'a': 'hello'}         # type: ignore
        assert config.asked_for == ['plugin1']

    def test_importing_and_configuring_more_than_one(self) -> None:
        self.make_file("plugin1.py", """\
            from coverage import CoveragePlugin

            class Plugin(CoveragePlugin):
                def __init__(self, options):
                    self.options = options
                    self.this_is = "me"

            def coverage_init(reg, options):
                reg.add_file_tracer(Plugin(options))
            """)
        self.make_file("plugin2.py", """\
            from coverage import CoveragePlugin

            class Plugin(CoveragePlugin):
                def __init__(self, options):
                    self.options = options

            def coverage_init(reg, options):
                reg.add_file_tracer(Plugin(options))
            """)

        config = FakeConfig("plugin1", {'a': 'hello'})
        plugins = list(Plugins.load_plugins(["plugin1", "plugin2"], config))

        assert len(plugins) == 2
        assert plugins[0].this_is == "me"                   # type: ignore
        assert plugins[0].options == {'a': 'hello'}         # type: ignore
        assert plugins[1].options == {}             # type: ignore
        assert config.asked_for == ['plugin1', 'plugin2']

        # The order matters...
        config = FakeConfig("plugin1", {'a': 'second'})
        plugins = list(Plugins.load_plugins(["plugin2", "plugin1"], config))

        assert len(plugins) == 2
        assert plugins[0].options == {}                     # type: ignore
        assert plugins[1].this_is == "me"                   # type: ignore
        assert plugins[1].options == {'a': 'second'}        # type: ignore

    def test_cant_import(self) -> None:
        with pytest.raises(ImportError, match="No module named '?plugin_not_there'?"):
            _ = Plugins.load_plugins(["plugin_not_there"], NullConfig())

    def test_plugin_must_define_coverage_init(self) -> None:
        self.make_file("no_plugin.py", """\
            from coverage import CoveragePlugin
            Nothing = 0
            """)
        msg_pat = "Plugin module 'no_plugin' didn't define a coverage_init function"
        with pytest.raises(PluginError, match=msg_pat):
            list(Plugins.load_plugins(["no_plugin"], NullConfig()))


class PluginTest(CoverageTest):
    """Test plugins through the Coverage class."""

    def test_plugin_imported(self) -> None:
        # Prove that a plugin will be imported.
        self.make_file("my_plugin.py", """\
            from coverage import CoveragePlugin
            class Plugin(CoveragePlugin):
                pass
            def coverage_init(reg, options):
                reg.add_noop(Plugin())
            with open("evidence.out", "w") as f:
                f.write("we are here!")
            """)

        self.assert_doesnt_exist("evidence.out")
        cov = coverage.Coverage()
        cov.set_option("run:plugins", ["my_plugin"])
        cov.start()
        cov.stop()      # pragma: nested

        with open("evidence.out") as f:
            assert f.read() == "we are here!"

    def test_missing_plugin_raises_import_error(self) -> None:
        # Prove that a missing plugin will raise an ImportError.
        with pytest.raises(ImportError, match="No module named '?does_not_exist_woijwoicweo'?"):
            cov = coverage.Coverage()
            cov.set_option("run:plugins", ["does_not_exist_woijwoicweo"])
            cov.start()
        cov.stop()

    def test_bad_plugin_isnt_hidden(self) -> None:
        # Prove that a plugin with an error in it will raise the error.
        self.make_file("plugin_over_zero.py", "1/0")
        with pytest.raises(ZeroDivisionError):
            cov = coverage.Coverage()
            cov.set_option("run:plugins", ["plugin_over_zero"])
            cov.start()
        cov.stop()

    def test_plugin_sys_info(self) -> None:
        self.make_file("plugin_sys_info.py", """\
            import coverage

            class Plugin(coverage.CoveragePlugin):
                def sys_info(self):
                    return [("hello", "world")]

            def coverage_init(reg, options):
                reg.add_file_tracer(Plugin())
            """)
        debug_out = io.StringIO()
        cov = coverage.Coverage(debug=["sys"])
        cov._debug_file = debug_out
        cov.set_option("run:plugins", ["plugin_sys_info"])
        with swallow_warnings(
            r"Plugin file tracers \(plugin_sys_info.Plugin\) aren't supported with PyTracer"
        ):
            cov.start()
        cov.stop()      # pragma: nested

        out_lines = [line.strip() for line in debug_out.getvalue().splitlines()]
        if env.C_TRACER:
            assert 'plugins.file_tracers: plugin_sys_info.Plugin' in out_lines
        else:
            assert 'plugins.file_tracers: plugin_sys_info.Plugin (disabled)' in out_lines
        assert 'plugins.configurers: -none-' in out_lines
        expected_end = [
            "-- sys: plugin_sys_info.Plugin -------------------------------",
            "hello: world",
            "-- end -------------------------------------------------------",
        ]
        assert expected_end == out_lines[-len(expected_end):]

    def test_plugin_with_no_sys_info(self) -> None:
        self.make_file("plugin_no_sys_info.py", """\
            import coverage

            class Plugin(coverage.CoveragePlugin):
                pass

            def coverage_init(reg, options):
                reg.add_configurer(Plugin())
            """)
        debug_out = io.StringIO()
        cov = coverage.Coverage(debug=["sys"])
        cov._debug_file = debug_out
        cov.set_option("run:plugins", ["plugin_no_sys_info"])
        cov.start()
        cov.stop()      # pragma: nested

        out_lines = [line.strip() for line in debug_out.getvalue().splitlines()]
        assert 'plugins.file_tracers: -none-' in out_lines
        assert 'plugins.configurers: plugin_no_sys_info.Plugin' in out_lines
        expected_end = [
            "-- sys: plugin_no_sys_info.Plugin ----------------------------",
            "-- end -------------------------------------------------------",
        ]
        assert expected_end == out_lines[-len(expected_end):]

    def test_local_files_are_importable(self) -> None:
        self.make_file("importing_plugin.py", """\
            from coverage import CoveragePlugin
            import local_module
            class MyPlugin(CoveragePlugin):
                pass
            def coverage_init(reg, options):
                reg.add_noop(MyPlugin())
            """)
        self.make_file("local_module.py", "CONST = 1")
        self.make_file(".coveragerc", """\
            [run]
            plugins = importing_plugin
            """)
        self.make_file("main_file.py", "print('MAIN')")

        out = self.run_command("coverage run main_file.py")
        assert out == "MAIN\n"
        out = self.run_command("coverage html -q")  # sneak in a test of -q
        assert out == ""


@pytest.mark.skipif(env.C_TRACER, reason="This test is only about PyTracer.")
class PluginWarningOnPyTracerTest(CoverageTest):
    """Test that we get a controlled exception with plugins on PyTracer."""
    def test_exception_if_plugins_on_pytracer(self) -> None:
        self.make_file("simple.py", "a = 1")

        cov = coverage.Coverage()
        cov.set_option("run:plugins", ["tests.plugin1"])

        expected_warnings = [
            r"Plugin file tracers \(tests.plugin1.Plugin\) aren't supported with PyTracer",
        ]
        with self.assert_warnings(cov, expected_warnings):
            self.start_import_stop(cov, "simple")


@pytest.mark.skipif(not env.C_TRACER, reason="Plugins are only supported with the C tracer.")
class FileTracerTest(CoverageTest):
    """Tests of plugins that implement file_tracer."""


class GoodFileTracerTest(FileTracerTest):
    """Tests of file tracer plugin happy paths."""

    def test_plugin1(self) -> None:
        self.make_file("simple.py", """\
            import try_xyz
            a = 1
            b = 2
            """)
        self.make_file("try_xyz.py", """\
            c = 3
            d = 4
            """)

        cov = coverage.Coverage()
        CheckUniqueFilenames.hook(cov, '_should_trace')
        CheckUniqueFilenames.hook(cov, '_check_include_omit_etc')
        cov.set_option("run:plugins", ["tests.plugin1"])

        # Import the Python file, executing it.
        self.start_import_stop(cov, "simple")

        _, statements, missing, _ = cov.analysis("simple.py")
        assert statements == [1, 2, 3]
        assert missing == []
        zzfile = os.path.abspath(os.path.join("/src", "try_ABC.zz"))
        _, statements, _, _ = cov.analysis(zzfile)
        assert statements == [105, 106, 107, 205, 206, 207]

    def make_render_and_caller(self) -> None:
        """Make the render.py and caller.py files we need."""
        # plugin2 emulates a dynamic tracing plugin: the caller's locals
        # are examined to determine the source file and line number.
        # The plugin is in tests/plugin2.py.
        self.make_file("render.py", """\
            def render(filename, linenum):
                # This function emulates a template renderer. The plugin
                # will examine the `filename` and `linenum` locals to
                # determine the source file and line number.
                fiddle_around = 1   # not used, just chaff.
                return "[{} @ {}]".format(filename, linenum)

            def helper(x):
                # This function is here just to show that not all code in
                # this file will be part of the dynamic tracing.
                return x+1
            """)
        self.make_file("caller.py", """\
            import sys
            from render import helper, render

            assert render("foo_7.html", 4) == "[foo_7.html @ 4]"
            # Render foo_7.html again to try the CheckUniqueFilenames asserts.
            render("foo_7.html", 4)

            assert helper(42) == 43
            assert render("bar_4.html", 2) == "[bar_4.html @ 2]"
            assert helper(76) == 77

            # quux_5.html will be omitted from the results.
            assert render("quux_5.html", 3) == "[quux_5.html @ 3]"
            """)

        # will try to read the actual source files, so make some
        # source files.
        def lines(n: int) -> str:
            """Make a string with n lines of text."""
            return "".join("line %d\n" % i for i in range(n))

        self.make_file("bar_4.html", lines(4))
        self.make_file("foo_7.html", lines(7))

    def test_plugin2(self) -> None:
        self.make_render_and_caller()

        cov = coverage.Coverage(omit=["*quux*"])
        CheckUniqueFilenames.hook(cov, '_should_trace')
        CheckUniqueFilenames.hook(cov, '_check_include_omit_etc')
        cov.set_option("run:plugins", ["tests.plugin2"])

        self.start_import_stop(cov, "caller")

        # The way plugin2 works, a file named foo_7.html will be claimed to
        # have 7 lines in it.  If render() was called with line number 4,
        # then the plugin will claim that lines 4 and 5 were executed.
        _, statements, missing, _ = cov.analysis("foo_7.html")
        assert statements == [1, 2, 3, 4, 5, 6, 7]
        assert missing == [1, 2, 3, 6, 7]
        assert "foo_7.html" in line_counts(cov.get_data())

        _, statements, missing, _ = cov.analysis("bar_4.html")
        assert statements == [1, 2, 3, 4]
        assert missing == [1, 4]
        assert "bar_4.html" in line_counts(cov.get_data())

        assert "quux_5.html" not in line_counts(cov.get_data())

    def test_plugin2_with_branch(self) -> None:
        self.make_render_and_caller()

        cov = coverage.Coverage(branch=True, omit=["*quux*"])
        CheckUniqueFilenames.hook(cov, '_should_trace')
        CheckUniqueFilenames.hook(cov, '_check_include_omit_etc')
        cov.set_option("run:plugins", ["tests.plugin2"])

        self.start_import_stop(cov, "caller")

        # The way plugin2 works, a file named foo_7.html will be claimed to
        # have 7 lines in it.  If render() was called with line number 4,
        # then the plugin will claim that lines 4 and 5 were executed.
        analysis = cov._analyze("foo_7.html")
        assert analysis.statements == {1, 2, 3, 4, 5, 6, 7}
        # Plugins don't do branch coverage yet.
        assert analysis.has_arcs() is True
        assert analysis.arc_possibilities() == []

        assert analysis.missing == {1, 2, 3, 6, 7}

    def test_plugin2_with_text_report(self) -> None:
        self.make_render_and_caller()

        cov = coverage.Coverage(branch=True, omit=["*quux*"])
        cov.set_option("run:plugins", ["tests.plugin2"])

        self.start_import_stop(cov, "caller")

        repout = io.StringIO()
        total = cov.report(file=repout, include=["*.html"], omit=["uni*.html"], show_missing=True)
        report = repout.getvalue().splitlines()
        expected = [
            'Name         Stmts   Miss Branch BrPart  Cover   Missing',
            '--------------------------------------------------------',
            'bar_4.html       4      2      0      0    50%   1, 4',
            'foo_7.html       7      5      0      0    29%   1-3, 6-7',
            '--------------------------------------------------------',
            'TOTAL           11      7      0      0    36%',
        ]
        assert expected == report
        assert math.isclose(total, 4 / 11 * 100)

    def test_plugin2_with_html_report(self) -> None:
        self.make_render_and_caller()

        cov = coverage.Coverage(branch=True, omit=["*quux*"])
        cov.set_option("run:plugins", ["tests.plugin2"])

        self.start_import_stop(cov, "caller")

        total = cov.html_report(include=["*.html"], omit=["uni*.html"])
        assert math.isclose(total, 4 / 11 * 100)

        self.assert_exists("htmlcov/index.html")
        self.assert_exists("htmlcov/bar_4_html.html")
        self.assert_exists("htmlcov/foo_7_html.html")

    def test_plugin2_with_xml_report(self) -> None:
        self.make_render_and_caller()

        cov = coverage.Coverage(branch=True, omit=["*quux*"])
        cov.set_option("run:plugins", ["tests.plugin2"])

        self.start_import_stop(cov, "caller")

        total = cov.xml_report(include=["*.html"], omit=["uni*.html"])
        assert math.isclose(total, 4 / 11 * 100)

        dom = ElementTree.parse("coverage.xml")
        classes = {}
        for elt in dom.findall(".//class"):
            classes[elt.get('name')] = elt

        assert classes['bar_4.html'].attrib == {
            'branch-rate': '1',
            'complexity': '0',
            'filename': 'bar_4.html',
            'line-rate': '0.5',
            'name': 'bar_4.html',
        }
        assert classes['foo_7.html'].attrib == {
            'branch-rate': '1',
            'complexity': '0',
            'filename': 'foo_7.html',
            'line-rate': '0.2857',
            'name': 'foo_7.html',
        }

    def test_defer_to_python(self) -> None:
        # A plugin that measures, but then wants built-in python reporting.
        self.make_file("fairly_odd_plugin.py", """\
            # A plugin that claims all the odd lines are executed, and none of
            # the even lines, and then punts reporting off to the built-in
            # Python reporting.
            import coverage.plugin
            class Plugin(coverage.CoveragePlugin):
                def file_tracer(self, filename):
                    return OddTracer(filename)
                def file_reporter(self, filename):
                    return "python"

            class OddTracer(coverage.plugin.FileTracer):
                def __init__(self, filename):
                    self.filename = filename
                def source_filename(self):
                    return self.filename
                def line_number_range(self, frame):
                    lineno = frame.f_lineno
                    if lineno % 2:
                        return (lineno, lineno)
                    else:
                        return (-1, -1)

            def coverage_init(reg, options):
                reg.add_file_tracer(Plugin())
            """)
        self.make_file("unsuspecting.py", """\
            a = 1
            b = 2
            c = 3
            d = 4
            e = 5
            f = 6
            """)
        cov = coverage.Coverage(include=["unsuspecting.py"])
        cov.set_option("run:plugins", ["fairly_odd_plugin"])
        self.start_import_stop(cov, "unsuspecting")

        repout = io.StringIO()
        total = cov.report(file=repout, show_missing=True)
        report = repout.getvalue().splitlines()
        expected = [
            'Name              Stmts   Miss  Cover   Missing',
            '-----------------------------------------------',
            'unsuspecting.py       6      3    50%   2, 4, 6',
            '-----------------------------------------------',
            'TOTAL                 6      3    50%',
        ]
        assert expected == report
        assert total == 50

    def test_find_unexecuted(self) -> None:
        self.make_file("unexecuted_plugin.py", """\
            import os
            import coverage.plugin
            class Plugin(coverage.CoveragePlugin):
                def file_tracer(self, filename):
                    if filename.endswith("foo.py"):
                        return MyTracer(filename)
                def file_reporter(self, filename):
                    return MyReporter(filename)
                def find_executable_files(self, src_dir):
                    # Check that src_dir is the right value
                    files = os.listdir(src_dir)
                    assert "foo.py" in files
                    assert "unexecuted_plugin.py" in files
                    return ["chimera.py"]

            class MyTracer(coverage.plugin.FileTracer):
                def __init__(self, filename):
                    self.filename = filename
                def source_filename(self):
                    return self.filename
                def line_number_range(self, frame):
                    return (999, 999)

            class MyReporter(coverage.FileReporter):
                def lines(self):
                    return {99, 999, 9999}

            def coverage_init(reg, options):
                reg.add_file_tracer(Plugin())
        """)
        self.make_file("foo.py", "a = 1")
        cov = coverage.Coverage(source=['.'])
        cov.set_option("run:plugins", ["unexecuted_plugin"])
        self.start_import_stop(cov, "foo")

        # The file we executed claims to have run line 999.
        _, statements, missing, _ = cov.analysis("foo.py")
        assert statements == [99, 999, 9999]
        assert missing == [99, 9999]

        # The completely missing file is in the results.
        _, statements, missing, _ = cov.analysis("chimera.py")
        assert statements == [99, 999, 9999]
        assert missing == [99, 999, 9999]

        # But completely new filenames are not in the results.
        assert len(cov.get_data().measured_files()) == 3
        with pytest.raises(NoSource):
            cov.analysis("fictional.py")


class BadFileTracerTest(FileTracerTest):
    """Test error handling around file tracer plugins."""

    def run_plugin(self, module_name: str) -> Coverage:
        """Run a plugin with the given module_name.

        Uses a few fixed Python files.

        Returns the Coverage object.

        """
        self.make_file("simple.py", """\
            import other, another
            a = other.f(2)
            b = other.f(3)
            c = another.g(4)
            d = another.g(5)
            """)
        # The names of these files are important: some plugins apply themselves
        # to "*other.py".
        self.make_file("other.py", """\
            def f(x):
                return x+1
            """)
        self.make_file("another.py", """\
            def g(x):
                return x-1
            """)

        cov = coverage.Coverage()
        cov.set_option("run:plugins", [module_name])
        self.start_import_stop(cov, "simple")
        cov.save()  # pytest-cov does a save after stop, so we'll do it too.
        return cov

    def run_bad_plugin(
        self,
        module_name: str,
        plugin_name: str,
        our_error: bool = True,
        excmsg: Optional[str] = None,
        excmsgs: Optional[List[str]] = None,
    ) -> None:
        """Run a file, and see that the plugin failed.

        `module_name` and `plugin_name` is the module and name of the plugin to
        use.

        `our_error` is True if the error reported to the user will be an
        explicit error in our test code, marked with an '# Oh noes!' comment.

        `excmsg`, if provided, is text that must appear in the stderr.

        `excmsgs`, if provided, is a list of messages, one of which must
        appear in the stderr.

        The plugin will be disabled, and we check that a warning is output
        explaining why.

        """
        with pytest.warns(Warning) as warns:
            self.run_plugin(module_name)

        stderr = self.stderr()
        stderr += "".join(str(w.message) for w in warns)
        if our_error:
            # The exception we're causing should only appear once.
            assert stderr.count("# Oh noes!") == 1

        # There should be a warning explaining what's happening, but only one.
        # The message can be in two forms:
        #   Disabling plug-in '...' due to previous exception
        # or:
        #   Disabling plug-in '...' due to an exception:
        print([str(w) for w in warns.list])
        warnings = [w for w in warns.list if issubclass(w.category, CoverageWarning)]
        assert len(warnings) == 1
        warnmsg = str(warnings[0].message)
        assert f"Disabling plug-in '{module_name}.{plugin_name}' due to " in warnmsg

        if excmsg:
            assert excmsg in stderr
        if excmsgs:
            found_exc = any(em in stderr for em in excmsgs)             #  pragma: part covered
            assert found_exc, f"expected one of {excmsgs} in stderr"

    def test_file_tracer_has_no_file_tracer_method(self) -> None:
        self.make_file("bad_plugin.py", """\
            class Plugin(object):
                pass

            def coverage_init(reg, options):
                reg.add_file_tracer(Plugin())
            """)
        self.run_bad_plugin("bad_plugin", "Plugin", our_error=False)

    def test_file_tracer_has_inherited_sourcefilename_method(self) -> None:
        self.make_file("bad_plugin.py", """\
            import coverage
            class Plugin(coverage.CoveragePlugin):
                def file_tracer(self, filename):
                    # Just grab everything.
                    return FileTracer()

            class FileTracer(coverage.FileTracer):
                pass

            def coverage_init(reg, options):
                reg.add_file_tracer(Plugin())
            """)
        self.run_bad_plugin(
            "bad_plugin", "Plugin", our_error=False,
            excmsg="Class 'bad_plugin.FileTracer' needs to implement source_filename()",
        )

    def test_plugin_has_inherited_filereporter_method(self) -> None:
        self.make_file("bad_plugin.py", """\
            import coverage
            class Plugin(coverage.CoveragePlugin):
                def file_tracer(self, filename):
                    # Just grab everything.
                    return FileTracer()

            class FileTracer(coverage.FileTracer):
                def source_filename(self):
                    return "foo.xxx"

            def coverage_init(reg, options):
                reg.add_file_tracer(Plugin())
            """)
        cov = self.run_plugin("bad_plugin")
        expected_msg = "Plugin 'bad_plugin.Plugin' needs to implement file_reporter()"
        with pytest.raises(NotImplementedError, match=expected_msg):
            cov.report()

    def test_file_tracer_fails(self) -> None:
        self.make_file("bad_plugin.py", """\
            import coverage.plugin
            class Plugin(coverage.plugin.CoveragePlugin):
                def file_tracer(self, filename):
                    17/0 # Oh noes!

            def coverage_init(reg, options):
                reg.add_file_tracer(Plugin())
            """)
        self.run_bad_plugin("bad_plugin", "Plugin")

    def test_file_tracer_fails_eventually(self) -> None:
        # Django coverage plugin can report on a few files and then fail.
        # https://github.com/nedbat/coveragepy/issues/1011
        self.make_file("bad_plugin.py", """\
            import os.path
            import coverage.plugin
            class Plugin(coverage.plugin.CoveragePlugin):
                def __init__(self):
                    self.calls = 0

                def file_tracer(self, filename):
                    print(filename)
                    self.calls += 1
                    if self.calls <= 2:
                        return FileTracer(filename)
                    else:
                        17/0 # Oh noes!

            class FileTracer(coverage.FileTracer):
                def __init__(self, filename):
                    self.filename = filename
                def source_filename(self):
                    return os.path.basename(self.filename).replace(".py", ".foo")
                def line_number_range(self, frame):
                    return -1, -1

            def coverage_init(reg, options):
                reg.add_file_tracer(Plugin())
            """)
        self.run_bad_plugin("bad_plugin", "Plugin")

    def test_file_tracer_returns_wrong(self) -> None:
        self.make_file("bad_plugin.py", """\
            import coverage.plugin
            class Plugin(coverage.plugin.CoveragePlugin):
                def file_tracer(self, filename):
                    return 3.14159

            def coverage_init(reg, options):
                reg.add_file_tracer(Plugin())
            """)
        self.run_bad_plugin(
            "bad_plugin", "Plugin", our_error=False, excmsg="'float' object has no attribute",
        )

    def test_has_dynamic_source_filename_fails(self) -> None:
        self.make_file("bad_plugin.py", """\
            import coverage.plugin
            class Plugin(coverage.plugin.CoveragePlugin):
                def file_tracer(self, filename):
                    return BadFileTracer()

            class BadFileTracer(coverage.plugin.FileTracer):
                def has_dynamic_source_filename(self):
                    23/0 # Oh noes!

            def coverage_init(reg, options):
                reg.add_file_tracer(Plugin())
            """)
        self.run_bad_plugin("bad_plugin", "Plugin")

    def test_source_filename_fails(self) -> None:
        self.make_file("bad_plugin.py", """\
            import coverage.plugin
            class Plugin(coverage.plugin.CoveragePlugin):
                def file_tracer(self, filename):
                    return BadFileTracer()

            class BadFileTracer(coverage.plugin.FileTracer):
                def source_filename(self):
                    42/0 # Oh noes!

            def coverage_init(reg, options):
                reg.add_file_tracer(Plugin())
            """)
        self.run_bad_plugin("bad_plugin", "Plugin")

    def test_source_filename_returns_wrong(self) -> None:
        self.make_file("bad_plugin.py", """\
            import coverage.plugin
            class Plugin(coverage.plugin.CoveragePlugin):
                def file_tracer(self, filename):
                    return BadFileTracer()

            class BadFileTracer(coverage.plugin.FileTracer):
                def source_filename(self):
                    return 17.3

            def coverage_init(reg, options):
                reg.add_file_tracer(Plugin())
            """)
        self.run_bad_plugin(
            "bad_plugin", "Plugin", our_error=False,
            excmsgs=[
                "expected str, bytes or os.PathLike object, not float",
                "'float' object has no attribute",
                "object of type 'float' has no len()",
                "'float' object is unsubscriptable",
            ],
        )

    def test_dynamic_source_filename_fails(self) -> None:
        self.make_file("bad_plugin.py", """\
            import coverage.plugin
            class Plugin(coverage.plugin.CoveragePlugin):
                def file_tracer(self, filename):
                    if filename.endswith("other.py"):
                        return BadFileTracer()

            class BadFileTracer(coverage.plugin.FileTracer):
                def has_dynamic_source_filename(self):
                    return True
                def dynamic_source_filename(self, filename, frame):
                    101/0 # Oh noes!

            def coverage_init(reg, options):
                reg.add_file_tracer(Plugin())
            """)
        self.run_bad_plugin("bad_plugin", "Plugin")

    def test_line_number_range_raises_error(self) -> None:
        self.make_file("bad_plugin.py", """\
            import coverage.plugin
            class Plugin(coverage.plugin.CoveragePlugin):
                def file_tracer(self, filename):
                    if filename.endswith("other.py"):
                        return BadFileTracer()

            class BadFileTracer(coverage.plugin.FileTracer):
                def source_filename(self):
                    return "something.foo"

                def line_number_range(self, frame):
                    raise Exception("borked!")

            def coverage_init(reg, options):
                reg.add_file_tracer(Plugin())
            """)
        self.run_bad_plugin(
            "bad_plugin", "Plugin", our_error=False, excmsg="borked!",
        )

    def test_line_number_range_returns_non_tuple(self) -> None:
        self.make_file("bad_plugin.py", """\
            import coverage.plugin
            class Plugin(coverage.plugin.CoveragePlugin):
                def file_tracer(self, filename):
                    if filename.endswith("other.py"):
                        return BadFileTracer()

            class BadFileTracer(coverage.plugin.FileTracer):
                def source_filename(self):
                    return "something.foo"

                def line_number_range(self, frame):
                    return 42.23

            def coverage_init(reg, options):
                reg.add_file_tracer(Plugin())
            """)
        self.run_bad_plugin(
            "bad_plugin", "Plugin", our_error=False, excmsg="line_number_range must return 2-tuple",
        )

    def test_line_number_range_returns_triple(self) -> None:
        self.make_file("bad_plugin.py", """\
            import coverage.plugin
            class Plugin(coverage.plugin.CoveragePlugin):
                def file_tracer(self, filename):
                    if filename.endswith("other.py"):
                        return BadFileTracer()

            class BadFileTracer(coverage.plugin.FileTracer):
                def source_filename(self):
                    return "something.foo"

                def line_number_range(self, frame):
                    return (1, 2, 3)

            def coverage_init(reg, options):
                reg.add_file_tracer(Plugin())
            """)
        self.run_bad_plugin(
            "bad_plugin", "Plugin", our_error=False, excmsg="line_number_range must return 2-tuple",
        )

    def test_line_number_range_returns_pair_of_strings(self) -> None:
        self.make_file("bad_plugin.py", """\
            import coverage.plugin
            class Plugin(coverage.plugin.CoveragePlugin):
                def file_tracer(self, filename):
                    if filename.endswith("other.py"):
                        return BadFileTracer()

            class BadFileTracer(coverage.plugin.FileTracer):
                def source_filename(self):
                    return "something.foo"

                def line_number_range(self, frame):
                    return ("5", "7")

            def coverage_init(reg, options):
                reg.add_file_tracer(Plugin())
            """)
        self.run_bad_plugin(
            "bad_plugin", "Plugin", our_error=False,
            excmsgs=[
                "an integer is required",
                "cannot be interpreted as an integer",
            ],
        )


class ConfigurerPluginTest(CoverageTest):
    """Test configuring plugins."""

    run_in_temp_dir = False

    def test_configurer_plugin(self) -> None:
        cov = coverage.Coverage()
        cov.set_option("run:plugins", ["tests.plugin_config"])
        cov.start()
        cov.stop()      # pragma: nested
        excluded = cov.get_option("report:exclude_lines")
        assert isinstance(excluded, list)
        assert "pragma: custom" in excluded
        assert "pragma: or whatever" in excluded


class DynamicContextPluginTest(CoverageTest):
    """Tests of plugins that implement `dynamic_context`."""

    def make_plugin_capitalized_testnames(self, filename: str) -> None:
        """Create a dynamic context plugin that capitalizes the part after 'test_'."""
        self.make_file(filename, """\
            from coverage import CoveragePlugin

            class Plugin(CoveragePlugin):
                def dynamic_context(self, frame):
                    name = frame.f_code.co_name
                    if name.startswith(("test_", "doctest_")):
                        parts = name.split("_", 1)
                        return "%s:%s" % (parts[0], parts[1].upper())
                    return None

            def coverage_init(reg, options):
                reg.add_dynamic_context(Plugin())
            """)

    def make_plugin_track_render(self, filename: str) -> None:
        """Make a dynamic context plugin that tracks 'render_' functions."""
        self.make_file(filename, """\
            from coverage import CoveragePlugin

            class Plugin(CoveragePlugin):
                def dynamic_context(self, frame):
                    name = frame.f_code.co_name
                    if name.startswith("render_"):
                        return 'renderer:' + name[7:]
                    return None

            def coverage_init(reg, options):
                reg.add_dynamic_context(Plugin())
            """)

    def make_test_files(self) -> None:
        """Make some files to use while testing dynamic context plugins."""
        self.make_file("rendering.py", """\
            def html_tag(tag, content):
                return f'<{tag}>{content}</{tag}>'

            def render_paragraph(text):
                return html_tag('p', text)

            def render_span(text):
                return html_tag('span', text)

            def render_bold(text):
                return html_tag('b', text)
            """)

        self.make_file("testsuite.py", """\
            import rendering

            def test_html_tag() -> None:
                assert rendering.html_tag('b', 'hello') == '<b>hello</b>'

            def doctest_html_tag():
                assert eval('''
                    rendering.html_tag('i', 'text') == '<i>text</i>'
                    '''.strip())

            def test_renderers() -> None:
                assert rendering.render_paragraph('hello') == '<p>hello</p>'
                assert rendering.render_bold('wide') == '<b>wide</b>'
                assert rendering.render_span('world') == '<span>world</span>'

            def build_full_html():
                html = '<html><body>%s</body></html>' % (
                   rendering.render_paragraph(
                      rendering.render_span('hello')))
                return html
            """)

    def run_all_functions(self, cov: Coverage, suite_name: str) -> None:    # pragma: nested
        """Run all functions in `suite_name` under coverage."""
        cov.start()
        suite = import_local_file(suite_name)
        try:
            # Call all functions in this module
            for name in dir(suite):
                variable = getattr(suite, name)
                if inspect.isfunction(variable):
                    variable()
        finally:
            cov.stop()

    def test_plugin_standalone(self) -> None:
        self.make_plugin_capitalized_testnames('plugin_tests.py')
        self.make_test_files()

        # Enable dynamic context plugin
        cov = coverage.Coverage()
        cov.set_option("run:plugins", ['plugin_tests'])

        # Run the tests
        self.run_all_functions(cov, 'testsuite')

        # Labeled coverage is collected
        data = cov.get_data()
        filenames = self.get_measured_filenames(data)
        expected = ['', 'doctest:HTML_TAG', 'test:HTML_TAG', 'test:RENDERERS']
        assert expected == sorted(data.measured_contexts())
        data.set_query_context("doctest:HTML_TAG")
        assert [2] == sorted_lines(data, filenames['rendering.py'])
        data.set_query_context("test:HTML_TAG")
        assert [2] == sorted_lines(data, filenames['rendering.py'])
        data.set_query_context("test:RENDERERS")
        assert [2, 5, 8, 11] == sorted_lines(data, filenames['rendering.py'])

    def test_static_context(self) -> None:
        self.make_plugin_capitalized_testnames('plugin_tests.py')
        self.make_test_files()

        # Enable dynamic context plugin for coverage with named context
        cov = coverage.Coverage(context='mytests')
        cov.set_option("run:plugins", ['plugin_tests'])

        # Run the tests
        self.run_all_functions(cov, 'testsuite')

        # Static context prefix is preserved
        data = cov.get_data()
        expected = [
            'mytests',
            'mytests|doctest:HTML_TAG',
            'mytests|test:HTML_TAG',
            'mytests|test:RENDERERS',
        ]
        assert expected == sorted(data.measured_contexts())

    def test_plugin_with_test_function(self) -> None:
        self.make_plugin_capitalized_testnames('plugin_tests.py')
        self.make_test_files()

        # Enable both a plugin and test_function dynamic context
        cov = coverage.Coverage()
        cov.set_option("run:plugins", ['plugin_tests'])
        cov.set_option("run:dynamic_context", "test_function")

        # Run the tests
        self.run_all_functions(cov, 'testsuite')

        # test_function takes precedence over plugins - only
        # functions that are not labeled by test_function are
        # labeled by plugin_tests.
        data = cov.get_data()
        filenames = self.get_measured_filenames(data)
        expected = [
            '',
            'doctest:HTML_TAG',
            'testsuite.test_html_tag',
            'testsuite.test_renderers',
        ]
        assert expected == sorted(data.measured_contexts())

        def assert_context_lines(context: str, lines: List[TLineNo]) -> None:
            data.set_query_context(context)
            assert lines == sorted_lines(data, filenames['rendering.py'])

        assert_context_lines("doctest:HTML_TAG", [2])
        assert_context_lines("testsuite.test_html_tag", [2])
        assert_context_lines("testsuite.test_renderers", [2, 5, 8, 11])

    def test_multiple_plugins(self) -> None:
        self.make_plugin_capitalized_testnames('plugin_tests.py')
        self.make_plugin_track_render('plugin_renderers.py')
        self.make_test_files()

        # Enable two plugins
        cov = coverage.Coverage()
        cov.set_option("run:plugins", ['plugin_renderers', 'plugin_tests'])

        self.run_all_functions(cov, 'testsuite')

        # It is important to note, that line 11 (render_bold function) is never
        # labeled as renderer:bold context, because it is only called from
        # test_renderers function - so it already falls under test:RENDERERS
        # context.
        #
        # render_paragraph and render_span (lines 5, 8) are directly called by
        # testsuite.build_full_html, so they get labeled by renderers plugin.
        data = cov.get_data()
        filenames = self.get_measured_filenames(data)
        expected = [
            '',
            'doctest:HTML_TAG',
            'renderer:paragraph',
            'renderer:span',
            'test:HTML_TAG',
            'test:RENDERERS',
        ]
        assert expected == sorted(data.measured_contexts())

        def assert_context_lines(context: str, lines: List[TLineNo]) -> None:
            data.set_query_context(context)
            assert lines == sorted_lines(data, filenames['rendering.py'])

        assert_context_lines("test:HTML_TAG", [2])
        assert_context_lines("test:RENDERERS", [2, 5, 8, 11])
        assert_context_lines("doctest:HTML_TAG", [2])
        assert_context_lines("renderer:paragraph", [2, 5])
        assert_context_lines("renderer:span", [2, 8])