kadence/desktop/tests/test_app_blocking.py

"""Blocking applications: the part that has to work the *second* time.

The bug these tests exist for: the manager used to remember every pid it had
dealt with and skip it forever, which made one cooldown do two jobs. The daily
report stayed readable — and a blocked app relaunched a moment later, or one
whose first signal was refused, ran untouched for the rest of the interval.

So the rules pinned here are:

* enforcement happens on **every** pass, reporting at most once per cooldown;
* a process is identified by (pid, start time), because pids are recycled;
* the kill escalates across passes (SIGTERM, then SIGKILL) and never blocks.

`FakeProcs` stands in for `/proc`: these tests must not need a victim process,
and the real module is covered by the fact that it reads files this one fakes.
"""

from __future__ import annotations

from dataclasses import dataclass, field

from kadence_desktop.blocking.manager import BlockerManager


@dataclass
class FakeApp:
    """What `processes.scan` returns, with its own notion of staying alive."""

    pid: int
    name: str
    matched: str
    start_time: int = 1000
    cmdline: str = ""
    #: Which signal it is prepared to ignore: "term", "kill", or neither.
    survives: str = ""

    @property
    def identity(self) -> tuple[int, int]:
        return (self.pid, self.start_time)


@dataclass
class FakeProcs:
    """A stand-in for `kadence_desktop.blocking.processes`."""

    running: list[FakeApp] = field(default_factory=list)
    signals: list[tuple[int, str]] = field(default_factory=list)

    def scan(self, patterns: list[str]) -> list[FakeApp]:
        return [app for app in self.running if app.matched in patterns]

    def terminate(self, app: FakeApp, *, force: bool = False) -> bool:
        self.signals.append((app.pid, "kill" if force else "term"))
        if force and app.survives == "kill":
            return False
        if not force and app.survives in ("term", "kill"):
            return True  # delivered, ignored — exactly what escalation is for
        self.running = [item for item in self.running if item.pid != app.pid]
        return True

    def alive(self, pid: int, started: int = 0) -> bool:
        return any(
            app.pid == pid and (started == 0 or app.start_time == started) for app in self.running
        )


def policy(*, apps=("steam*",), kill: bool = True, poll_seconds: int = 3) -> dict:
    return {
        "active": True,
        "enabled": True,
        "domains": [],
        "apps": list(apps),
        "kill_apps": kill,
        "redirect_ip": "127.0.0.1",
        "unexpandable": [],
        "allowed": [],
        "poll_seconds": poll_seconds,
    }


def manager(procs: FakeProcs, reports: list, **kwargs) -> BlockerManager:
    class NoDns:
        running = False
        port = 0
        error = None
        applied = None

        def start(self) -> bool:
            return True

        def stop(self) -> None:
            pass

        def set_rules(self, *args, **kwargs) -> None:
            pass

        def on(self, *args) -> bool:
            return True

        def off(self) -> bool:
            return True

    return BlockerManager(
        helper_path="/nonexistent/kadence-helper",
        report=lambda kind, target, action, details: reports.append((kind, target, action)),
        stub=NoDns(),
        route=NoDns(),
        procs=procs,
        **kwargs,
    )


def test_the_second_launch_is_closed_too():
    """The bug, stated as a test: relaunching inside the cooldown must not work."""
    procs = FakeProcs([FakeApp(pid=101, name="steam", matched="steam*")])
    reports: list = []
    blocker = manager(procs, reports)

    blocker.sync(policy())
    assert procs.signals == [(101, "term")]
    assert procs.running == []

    # A second launch, a moment later: a new process, a recycled-or-not pid.
    procs.running = [FakeApp(pid=101, name="steam", matched="steam*", start_time=2000)]
    blocker.enforce_apps_now()

    assert procs.signals == [(101, "term"), (101, "term")]
    assert procs.running == []


def test_a_pid_is_not_an_identity():
    """Same pid, same start time is one process; a new start time is another."""
    procs = FakeProcs([FakeApp(pid=7, name="steam", matched="steam*", start_time=42)])
    reports: list = []
    blocker = manager(procs, reports)

    blocker.sync(policy())
    assert reports == [("app", "steam*", "killed")]

    # Reusing the pid *and* the start time cannot happen on a real machine; the
    # point is that the bookkeeping keys on both, so this one is throttled...
    procs.running = [FakeApp(pid=7, name="steam", matched="steam*", start_time=42)]
    blocker.enforce_apps_now()
    assert reports == [("app", "steam*", "killed")]

    # ...while a genuinely new process is reported again.
    procs.running = [FakeApp(pid=7, name="steam", matched="steam*", start_time=99)]
    blocker.enforce_apps_now()
    assert reports == [("app", "steam*", "killed"), ("app", "steam*", "killed")]


def test_the_report_is_throttled_but_the_block_is_not():
    """One row in the evening report; one signal per pass regardless."""
    stubborn = FakeApp(pid=55, name="steam", matched="steam*", survives="kill")
    procs = FakeProcs([stubborn])
    reports: list = []
    blocker = manager(procs, reports, kill_grace=0.0)

    for _ in range(4):
        blocker.sync(policy())

    assert len(reports) == 1, reports
    # SIGTERM once, then SIGKILL on every pass after the grace — it is still
    # there, so the manager keeps insisting.
    assert procs.signals == [(55, "term"), (55, "kill"), (55, "kill"), (55, "kill")]


def test_sigkill_only_after_the_grace_period():
    """A well-behaved app gets time to quit before anything is forced."""
    procs = FakeProcs([FakeApp(pid=8, name="steam", matched="steam*", survives="term")])
    reports: list = []
    blocker = manager(procs, reports, kill_grace=600.0)

    blocker.sync(policy())
    blocker.enforce_apps_now()
    blocker.enforce_apps_now()

    assert procs.signals == [(8, "term")], "nothing may be forced inside the grace"


def test_a_refused_signal_is_retried_rather_than_exempting_the_process():
    """`terminate` saying no must not be a free pass for the interval."""
    procs = FakeProcs([FakeApp(pid=9, name="steam", matched="steam*", survives="kill")])
    reports: list = []
    blocker = manager(procs, reports, kill_grace=0.0, report_cooldown=0.0)

    blocker.sync(policy())
    assert reports == [("app", "steam*", "killed")]
    blocker.enforce_apps_now()

    assert procs.signals == [(9, "term"), (9, "kill")]
    assert len(reports) == 2


def test_warn_mode_never_kills():
    procs = FakeProcs([FakeApp(pid=11, name="discord", matched="*discord*")])
    reports: list = []
    blocker = manager(procs, reports)

    blocker.sync(policy(apps=("*discord*",), kill=False))

    assert procs.signals == []
    assert procs.running  # still there, by design
    assert reports == [("app", "*discord*", "warned")]
    assert blocker.killed_today == 0


def test_nothing_is_enforced_once_the_interval_ends():
    procs = FakeProcs([FakeApp(pid=12, name="steam", matched="steam*")])
    reports: list = []
    blocker = manager(procs, reports)

    blocker.sync(policy() | {"active": False})
    blocker.enforce_apps_now()

    assert procs.signals == []
    assert reports == []


def test_the_books_do_not_grow_for_processes_that_are_gone():
    procs = FakeProcs([FakeApp(pid=i, name="steam", matched="steam*") for i in range(20, 25)])
    reports: list = []
    blocker = manager(procs, reports)

    blocker.sync(policy())
    assert len(reports) == 5
    # Everything was closed, so the next pass has nothing left to remember.
    blocker.enforce_apps_now()

    assert blocker._reported == {}
    assert blocker._asked == {}