Initial code commit

tests/unit/test_cli.py

@@ -0,0 +1,122 @@
+from __future__ import annotations
+
+import pytest
+
+from schedls.cli import _parse_environment, _spec_for_new, build_parser, main, split_command
+from schedls.errors import InvalidNameError, UsageError
+from schedls.models import Backend, Scope
+
+
+def test_split_command() -> None:
+    head, tail = split_command(["new", "x", "--timer", "--", "/bin/true", "arg"])
+    assert head == ["new", "x", "--timer"]
+    assert tail == ["/bin/true", "arg"]
+    head, tail = split_command(["show", "x"])
+    assert head == ["show", "x"]
+    assert tail == []
+
+
+def test_edit_command_dest_does_not_shadow_subcommand() -> None:
+    args = build_parser().parse_args(["edit", "backup", "--command"])
+    assert args.command == "edit"
+    assert args.replace_command is True
+
+
+def test_spec_for_new_systemd() -> None:
+    args = build_parser().parse_args(["new", "backup", "--timer", "--daily", "02:00", "--persistent"])
+    spec = _spec_for_new(args, ["/usr/local/bin/backup", "/srv/data"])
+    assert spec.backend is Backend.SYSTEMD
+    assert spec.scope is Scope.USER
+    assert spec.calendar == ("*-*-* 02:00:00",)
+    assert spec.command.argv == ("/usr/local/bin/backup", "/srv/data")
+    assert spec.persistent is True
+
+
+def test_spec_for_new_cron() -> None:
+    args = build_parser().parse_args(["new", "cleanup", "--cron", "--cron-expr", "0 4 * * 0"])
+    spec = _spec_for_new(args, ["/usr/local/bin/cleanup"])
+    assert spec.backend is Backend.CRON
+    assert spec.cron_expression == "0 4 * * 0"
+
+
+def test_spec_for_new_system_scope() -> None:
+    args = build_parser().parse_args(["new", "x", "--timer", "--daily", "02:00", "--system"])
+    spec = _spec_for_new(args, ["/bin/true"])
+    assert spec.scope is Scope.SYSTEM
+
+
+def test_spec_for_new_invalid_name() -> None:
+    args = build_parser().parse_args(["new", "../evil", "--timer", "--daily", "02:00"])
+    with pytest.raises(InvalidNameError):
+        _spec_for_new(args, ["/bin/true"])
+
+
+def test_spec_for_new_requires_schedule() -> None:
+    args = build_parser().parse_args(["new", "x", "--timer"])
+    with pytest.raises(UsageError):
+        _spec_for_new(args, ["/bin/true"])
+
+
+def test_new_without_backend_is_usage_error() -> None:
+    assert main(["new", "x", "--daily", "02:00"]) == 2
+
+
+def test_new_without_name_is_usage_error() -> None:
+    assert main(["new", "--timer", "--daily", "02:00"]) == 2
+
+
+def test_interactive_conflicts_with_json() -> None:
+    assert main(["--json", "new", "x", "-i", "--timer", "--daily", "02:00"]) == 2
+
+
+def test_interactive_requires_terminal(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setattr("sys.stdin", _FakeStdin(isatty=False))
+    assert main(["new", "x", "-i", "--timer", "--daily", "02:00"]) == 3
+
+
+class _FakeStdin:
+    def __init__(self, *, isatty: bool) -> None:
+        self._isatty = isatty
+
+    def isatty(self) -> bool:
+        return self._isatty
+
+
+def test_spec_for_new_shell_mode() -> None:
+    args = build_parser().parse_args(["new", "x", "--timer", "--daily", "02:00", "--shell", "echo hi | cat"])
+    spec = _spec_for_new(args, [])
+    assert spec.command.shell is True
+    assert spec.command.raw == "echo hi | cat"
+
+
+def test_spec_for_new_rejects_systemd_flags_for_cron() -> None:
+    for extra in (["--env", "A=1"], ["--working-directory", "/srv/data"], ["--persistent"], ["--jitter", "5min"]):
+        args = build_parser().parse_args(["new", "x", "--cron", "--daily", "02:00", *extra])
+        with pytest.raises(UsageError):
+            _spec_for_new(args, ["/bin/true"])
+
+
+def test_spec_for_new_rejects_cron_expr_for_timer() -> None:
+    args = build_parser().parse_args(["new", "x", "--timer", "--cron-expr", "0 4 * * *"])
+    with pytest.raises(UsageError):
+        _spec_for_new(args, ["/bin/true"])
+
+
+def test_spec_for_new_rejects_system_scope_for_cron() -> None:
+    args = build_parser().parse_args(["new", "x", "--cron", "--daily", "02:00", "--system"])
+    with pytest.raises(UsageError):
+        _spec_for_new(args, ["/bin/true"])
+
+
+@pytest.mark.parametrize("value", ["0", "-1", "1000001", "abc"])
+def test_logs_lines_must_be_a_bounded_positive_integer(value: str) -> None:
+    with pytest.raises(SystemExit):
+        build_parser().parse_args(["logs", "x", "--lines", value])
+
+
+def test_parse_environment() -> None:
+    assert _parse_environment(["A=1", "B=x=y"]) == (("A", "1"), ("B", "x=y"))
+    with pytest.raises(UsageError):
+        _parse_environment(["NOVALUE"])
+    with pytest.raises(UsageError):
+        _parse_environment(["1BAD=1"])

tests/unit/test_convenience.py

@@ -0,0 +1,43 @@
+from __future__ import annotations
+
+import pytest
+
+from schedls import convenience
+from schedls.errors import InvalidScheduleError
+
+
+@pytest.mark.parametrize(
+    ("time", "expected"),
+    [("02:00", "*-*-* 02:00:00"), ("2:05", "*-*-* 02:05:00"), ("23:59:59", "*-*-* 23:59:59")],
+)
+def test_daily_calendar(time: str, expected: str) -> None:
+    assert convenience.daily_calendar(time) == expected
+
+
+def test_weekdays_and_weekly_calendar() -> None:
+    assert convenience.weekdays_calendar("08:30") == "Mon..Fri *-*-* 08:30:00"
+    assert convenience.weekly_calendar("sun", "04:00") == "Sun *-*-* 04:00:00"
+    assert convenience.weekly_calendar("Saturday", "4:00") == "Sat *-*-* 04:00:00"
+    assert convenience.monthly_calendar("1", "06:00") == "*-*-01 06:00:00"
+
+
+def test_cron_variants() -> None:
+    assert convenience.daily_cron("02:00") == "0 2 * * *"
+    assert convenience.weekdays_cron("08:30") == "30 8 * * 1-5"
+    assert convenience.weekly_cron("sun", "04:00") == "0 4 * * 0"
+    assert convenience.monthly_cron("15", "06:00") == "0 6 15 * *"
+
+
+@pytest.mark.parametrize("bad", ["25:00", "02:60", "nope", "2", "02:00:99"])
+def test_invalid_time(bad: str) -> None:
+    with pytest.raises(InvalidScheduleError):
+        convenience.daily_calendar(bad)
+
+
+def test_invalid_weekday_and_day() -> None:
+    with pytest.raises(InvalidScheduleError):
+        convenience.weekly_calendar("funday", "04:00")
+    with pytest.raises(InvalidScheduleError):
+        convenience.monthly_calendar("32", "06:00")
+    with pytest.raises(InvalidScheduleError):
+        convenience.monthly_calendar("x", "06:00")

tests/unit/test_crontab.py

@@ -0,0 +1,95 @@
+from __future__ import annotations
+
+import pytest
+
+from schedls.backends.cron import CrontabDocument
+from schedls.errors import ConflictError, SafetyRefusalError
+
+SAMPLE = (
+    "MAILTO=admin@example.net\n"
+    "SHELL=/bin/bash\n"
+    "PATH=/usr/local/bin:/usr/bin\n"
+    "\n"
+    "# personal job\n"
+    "15 7 * * * ~/bin/foo\n"
+    "@daily /usr/local/bin/nightly\n"
+    "\n"
+    "# schedls:begin name=backup\n"
+    "0 2 * * * /usr/local/bin/backup /srv/data\n"
+    "# schedls:end name=backup\n"
+)
+
+
+def test_lossless_round_trip() -> None:
+    document = CrontabDocument(SAMPLE)
+    assert document.render() == SAMPLE
+
+
+def test_managed_block_detected() -> None:
+    document = CrontabDocument(SAMPLE)
+    blocks = document.managed_blocks()
+    assert list(blocks) == ["backup"]
+    assert blocks["backup"].job_lines[0].expression == "0 2 * * *"
+    assert blocks["backup"].job_lines[0].command == "/usr/local/bin/backup /srv/data"
+    assert not document.has_malformed_markers()
+
+
+def test_environment_and_nickname_parsed() -> None:
+    document = CrontabDocument(SAMPLE)
+    kinds = [entry.kind for entry in document.entries]
+    assert kinds.count("env") == 3
+    assert kinds.count("comment") == 1
+    assert kinds.count("managed_begin") == 1
+    assert kinds.count("managed_end") == 1
+    jobs = [entry for entry in document.entries if entry.kind == "job"]
+    assert jobs[0].expression == "15 7 * * *"
+    assert jobs[1].expression == "@daily"
+
+
+def test_with_block_preserves_unrelated_content() -> None:
+    document = CrontabDocument(SAMPLE)
+    updated = document.with_block("report", ["30 6 * * * /usr/local/bin/report"])
+    assert "MAILTO=admin@example.net" in updated
+    assert "15 7 * * * ~/bin/foo" in updated
+    assert "0 2 * * * /usr/local/bin/backup /srv/data" in updated
+    assert "# schedls:begin name=report" in updated
+    reparsed = CrontabDocument(updated)
+    assert set(reparsed.managed_blocks()) == {"backup", "report"}
+
+
+def test_with_block_conflict() -> None:
+    document = CrontabDocument(SAMPLE)
+    with pytest.raises(ConflictError):
+        document.with_block("backup", ["0 3 * * * /bin/true"])
+
+
+def test_without_block_removes_only_block() -> None:
+    document = CrontabDocument(SAMPLE)
+    updated = document.without_block("backup")
+    assert "backup" not in updated
+    assert "MAILTO=admin@example.net" in updated
+    assert "15 7 * * * ~/bin/foo" in updated
+    assert "@daily /usr/local/bin/nightly" in updated
+
+
+def test_without_unknown_block_refused() -> None:
+    document = CrontabDocument(SAMPLE)
+    with pytest.raises(SafetyRefusalError):
+        document.without_block("nope")
+
+
+def test_malformed_marker_blocks_mutation() -> None:
+    document = CrontabDocument("# schedls:begin name=broken\n0 2 * * * /bin/true\n")
+    assert document.has_malformed_markers()
+    with pytest.raises(SafetyRefusalError):
+        document.with_block("new", ["0 3 * * * /bin/true"])
+    with pytest.raises(SafetyRefusalError):
+        document.without_block("broken")
+
+
+def test_empty_crontab() -> None:
+    document = CrontabDocument("")
+    assert document.render() == ""
+    updated = document.with_block("x", ["0 0 * * * /bin/true"])
+    assert updated.endswith("\n")
+    assert "name=x" in updated

tests/unit/test_describe.py

@@ -0,0 +1,28 @@
+from __future__ import annotations
+
+from schedls.describe import describe_calendar, describe_cron, describe_schedule
+from schedls.models import Schedule, ScheduleKind
+
+
+def test_describe_calendar() -> None:
+    assert describe_calendar("*-*-* 02:00:00") == "daily at 02:00"
+    assert describe_calendar("Mon..Fri *-*-* 08:30:00") == "weekdays at 08:30"
+    assert describe_calendar("Sun *-*-* 04:00:00") == "Sunday at 04:00"
+    assert describe_calendar("*-*-01 06:00:00") == "monthly on day 1 at 06:00"
+    assert describe_calendar("*-*-* *:00:00") is None
+
+
+def test_describe_cron() -> None:
+    assert describe_cron("0 2 * * *") == "daily at 02:00"
+    assert describe_cron("30 8 * * 1-5") == "weekdays at 08:30"
+    assert describe_cron("0 4 * * 0") == "Sunday at 04:00"
+    assert describe_cron("0 6 15 * *") == "monthly on day 15 at 06:00"
+    assert describe_cron("0 4 1,15 * 5") is None
+    assert describe_cron("@daily") is None
+
+
+def test_describe_schedule() -> None:
+    assert describe_schedule(Schedule(ScheduleKind.CALENDAR, "*-*-* 02:00:00")) == "daily at 02:00"
+    assert describe_schedule(Schedule(ScheduleKind.CRON, "@reboot")) == "@reboot"
+    multi = Schedule(ScheduleKind.CALENDAR, "A", ("A", "B"))
+    assert describe_schedule(multi) == "A + B"

tests/unit/test_operations.py

@@ -0,0 +1,393 @@
+from __future__ import annotations
+
+import io
+import os
+import tempfile
+from dataclasses import replace
+
+import pytest
+
+from schedls.backends.base import CommandPlan, FileChange, MutationResult, Plan
+from schedls.backends.cron import CronBackend
+from schedls.backends.systemd import SystemdBackend
+from schedls.errors import InvalidScheduleError, OperationalError, SafetyRefusalError
+from schedls.interact import Interaction
+from schedls.models import (
+    Backend,
+    Command,
+    JobSource,
+    JobSpec,
+    Schedule,
+    ScheduledJob,
+    ScheduleKind,
+    Scope,
+    SystemdDetails,
+)
+from schedls.operations import doctor as doctor_ops
+from schedls.operations import inspect as inspect_ops
+from schedls.operations import mutate as mutate_ops
+from schedls.output import Output
+
+from ..conftest import FakeRunner
+
+
+def _job(name: str = "backup") -> ScheduledJob:
+    return ScheduledJob(
+        name=name,
+        backend=Backend.SYSTEMD,
+        scope=Scope.USER,
+        managed=True,
+        enabled=True,
+        schedule=Schedule(ScheduleKind.CALENDAR, "*-*-* 02:00:00"),
+        command=Command(argv=("/usr/local/bin/backup",)),
+        source=JobSource("systemd user timer"),
+    )
+
+
+def _output() -> tuple[Output, io.StringIO]:
+    stream = io.StringIO()
+    return Output(color="never", stdout=stream), stream
+
+
+def test_render_list_table() -> None:
+    output, stream = _output()
+    inspect_ops.render_list(output, [_job(), _job("cleanup")], [])
+    text = stream.getvalue()
+    assert "NAME" in text and "SCHEDULE" in text
+    assert "backup" in text and "cleanup" in text
+
+
+def test_render_list_json() -> None:
+    output, stream = _output()
+    output.json_mode = True
+    inspect_ops.render_list(output, [_job()], ["note"])
+    assert '"schema_version": 1' in stream.getvalue()
+
+
+def test_render_show() -> None:
+    output, stream = _output()
+    inspect_ops.render_show(output, _job())
+    text = stream.getvalue()
+    assert "Managed by schedls" in text
+    assert "systemd user timer" in text
+
+
+def test_filter_jobs() -> None:
+    jobs = [_job(), _job("other")]
+    assert inspect_ops.filter_jobs(jobs, managed=True) == jobs
+    assert inspect_ops.filter_jobs(jobs, managed=False) == []
+    assert inspect_ops.filter_jobs(jobs, enabled=False) == []
+    assert len(inspect_ops.filter_jobs(jobs, backend=Backend.SYSTEMD)) == 2
+
+
+def test_collect_reports_unavailable_backend() -> None:
+    backend = SystemdBackend(FakeRunner())
+    jobs, warnings = inspect_ops.collect([backend], [Scope.USER])
+    assert jobs == []
+    assert any("unavailable" in warning for warning in warnings)
+
+
+class _DummyBackend:
+    name = "systemd"
+
+    def __init__(self, result: MutationResult) -> None:
+        self.result = result
+        self.applied = False
+
+    def apply(self, plan: Plan) -> MutationResult:
+        self.applied = True
+        return self.result
+
+
+def test_run_plan_dry_run(tmp_path) -> None:
+    output, stream = _output()
+    plan = Plan(backend="systemd", action="create")
+    plan.files = [FileChange(str(tmp_path / "example.service"), "data")]
+    plan.commands = [CommandPlan(("systemctl", "reload"), "reload")]
+    backend = _DummyBackend(MutationResult(changed=True))
+    result = mutate_ops.run_plan(backend, plan, output, Interaction(output=output), dry_run=True)
+    assert result.dry_run is True
+    assert backend.applied is False
+    assert "No changes made." in stream.getvalue()
+
+
+def test_run_plan_confirms_and_applies() -> None:
+    output, stream = _output()
+    plan = Plan(backend="systemd", action="create")
+    backend = _DummyBackend(MutationResult(changed=True, messages=["done"]))
+    interaction = Interaction(output=output, assume_yes=True)
+    result = mutate_ops.run_plan(backend, plan, output, interaction)
+    assert backend.applied is True
+    assert result.changed is True
+    assert "done" in stream.getvalue()
+
+
+def test_run_plan_json_mode() -> None:
+    output, stream = _output()
+    output.json_mode = True
+    plan = Plan(backend="systemd", action="create")
+    backend = _DummyBackend(MutationResult(changed=True))
+    mutate_ops.run_plan(backend, plan, output, Interaction(output=output, assume_yes=True))
+    assert '"action": "create"' in stream.getvalue()
+
+
+def _doctor_runner() -> FakeRunner:
+    def systemctl(argv, _input):
+        if "is-system-running" in argv:
+            return ("running\n", "")
+        return ("", "")
+
+    def crontab(argv, _input):
+        if "-V" in argv:
+            return ("cronie 1.7.2\n", "")
+        return ("", "")
+
+    return FakeRunner(
+        handlers={
+            "systemctl": systemctl,
+            "crontab": crontab,
+            "loginctl": lambda argv, _input: ("Linger=no\n", ""),
+        },
+        available={"systemctl", "systemd-analyze", "crontab", "loginctl"},
+    )
+
+
+def test_doctor_human() -> None:
+    runner = _doctor_runner()
+    output, stream = _output()
+    doctor_ops.run_doctor(runner, output, SystemdBackend(runner), CronBackend(runner))
+    text = stream.getvalue()
+    assert "Cronie" in text
+    assert "usable" in text
+
+
+def test_doctor_json() -> None:
+    runner = _doctor_runner()
+    output, stream = _output()
+    output.json_mode = True
+    doctor_ops.run_doctor(runner, output, SystemdBackend(runner), CronBackend(runner))
+    assert '"result": "usable"' in stream.getvalue()
+
+
+def test_systemd_backend_discovery_parses_units() -> None:
+    timer = (
+        "# Managed by schedls\n"
+        "# Name: backup\n"
+        "[Unit]\nDescription=foo\n[Timer]\nOnCalendar=*-*-* 02:00:00\nPersistent=true\nUnit=schedls-backup.service\n"
+    )
+    service = '[Service]\nExecStart="/usr/local/bin/backup" "/srv/data"\n'
+
+    with tempfile.TemporaryDirectory() as tmp:
+        timer_path = os.path.join(tmp, "schedls-backup.timer")
+        service_path = os.path.join(tmp, "schedls-backup.service")
+        with open(timer_path, "w") as handle:
+            handle.write(timer)
+        with open(service_path, "w") as handle:
+            handle.write(service)
+
+        def systemctl(argv, _input):
+            if "is-system-running" in argv:
+                return ("running\n", "")
+            if "list-unit-files" in argv or "list-units" in argv:
+                return ("schedls-backup.timer enabled\n", "")
+            if "show" in argv:
+                unit = argv[argv.index("show") + 1]
+                if unit.endswith(".timer"):
+                    return (
+                        f"Id={unit}\nLoadState=loaded\nFragmentPath={timer_path}\n"
+                        "UnitFileState=enabled\nActiveState=active\nSubState=waiting\n"
+                        "NextElapseUSecRealtime=1758700800000000\nTriggers=schedls-backup.service\n",
+                        "",
+                    )
+                return (
+                    f"Id={unit}\nLoadState=loaded\nFragmentPath={service_path}\nResult=success\n",
+                    "",
+                )
+            return ("", "")
+
+        runner = FakeRunner(handlers={"systemctl": systemctl}, available={"systemctl"})
+        backend = SystemdBackend(runner)
+        jobs = backend.discover([Scope.USER])
+        assert len(jobs) == 1
+        job = jobs[0]
+        assert job.name == "backup"
+        assert job.managed is True
+        assert job.schedule.expression == "*-*-* 02:00:00"
+        assert job.command.argv == ("/usr/local/bin/backup", "/srv/data")
+        assert job.enabled is True
+        assert job.next_run is not None
+
+
+def test_plan_update_refuses_unmanaged() -> None:
+    runner = FakeRunner()
+    backend = SystemdBackend(runner)
+    unmanaged = replace(_job("certbot"), managed=False)
+    spec = JobSpec(
+        name="certbot",
+        backend=Backend.SYSTEMD,
+        scope=Scope.USER,
+        command=Command(argv=("/bin/true",)),
+        calendar=("*-*-* 01:00:00",),
+    )
+    with pytest.raises(SafetyRefusalError):
+        backend.plan_update(unmanaged, spec)
+
+
+def _managed_job(name: str = "backup", *, scope: Scope = Scope.USER, service_unit: str | None = None) -> ScheduledJob:
+    return replace(
+        _job(name),
+        scope=scope,
+        systemd=SystemdDetails(
+            timer_unit=f"schedls-{name}.timer",
+            service_unit=service_unit or f"schedls-{name}.service",
+            on_calendar=("*-*-* 02:00:00",),
+        ),
+    )
+
+
+def _spec(name: str = "backup") -> JobSpec:
+    return JobSpec(
+        name=name,
+        backend=Backend.SYSTEMD,
+        scope=Scope.USER,
+        command=Command(argv=("/bin/true",)),
+        calendar=("*-*-* 03:00:00",),
+    )
+
+
+def _analyze_runner() -> FakeRunner:
+    def analyze(argv, _input):
+        if "calendar" in argv:
+            return ("Normalized form: *-*-* 03:00:00\n", "")
+        return ("", "")
+
+    return FakeRunner(handlers={"systemd-analyze": analyze}, available={"systemd-analyze"})
+
+
+def test_plan_update_derives_unit_names(tmp_path, monkeypatch) -> None:
+    monkeypatch.setenv("XDG_CONFIG_HOME", str(tmp_path))
+    backend = SystemdBackend(_analyze_runner())
+    job = _managed_job(service_unit="../../../../tmp/evil.service")
+    plan = backend.plan_update(job, _spec())
+    expected_dir = os.path.join(str(tmp_path), "systemd", "user")
+    assert sorted(change.path for change in plan.files) == [
+        os.path.join(expected_dir, "schedls-backup.service"),
+        os.path.join(expected_dir, "schedls-backup.timer"),
+    ]
+    assert "evil" not in " ".join(change.path for change in plan.files)
+
+
+def test_verify_units_rejects_traversal() -> None:
+    backend = SystemdBackend(_analyze_runner())
+    with pytest.raises(SafetyRefusalError):
+        backend._verify_units({"../../evil.service": "content"})
+
+
+def test_unit_dir_rejects_relative_xdg(monkeypatch) -> None:
+    monkeypatch.setenv("XDG_CONFIG_HOME", "relative")
+    backend = SystemdBackend(FakeRunner())
+    with pytest.raises(SafetyRefusalError):
+        backend._unit_dir(Scope.USER)
+
+
+def test_plan_update_requires_scope(monkeypatch) -> None:
+    monkeypatch.setattr(os, "geteuid", lambda: 1000)
+    backend = SystemdBackend(_analyze_runner())
+    with pytest.raises(SafetyRefusalError):
+        backend.plan_update(_managed_job(scope=Scope.SYSTEM), _spec())
+
+
+def test_validate_spec_rejects_unsafe_calendar() -> None:
+    backend = SystemdBackend(FakeRunner())
+    spec = replace(_spec(), calendar=("-x",))
+    with pytest.raises(InvalidScheduleError):
+        backend._validate_spec(spec)
+
+
+def test_validate_spec_rejects_unsafe_jitter() -> None:
+    backend = SystemdBackend(_analyze_runner())
+    for jitter in ("5min\nExecStart=/bin/true", "-5min"):
+        with pytest.raises(InvalidScheduleError):
+            backend._validate_spec(replace(_spec(), jitter=jitter))
+
+
+def test_apply_rolls_back_on_keyboard_interrupt(tmp_path) -> None:
+    target = tmp_path / "schedls-backup.service"
+    raised = []
+
+    def systemctl(argv, _input):
+        if not raised:
+            raised.append(True)
+            raise KeyboardInterrupt
+        return ("", "")
+
+    runner = FakeRunner(handlers={"systemctl": systemctl}, available={"systemctl"})
+    backend = SystemdBackend(runner)
+    plan = Plan(backend="systemd", action="update")
+    plan.files = [FileChange(str(target), "content", mode=0o600)]
+    plan.commands = [CommandPlan(("systemctl", "daemon-reload"), "reload")]
+    plan.payload = {"scope": Scope.USER, "snapshots": {}}
+    with pytest.raises(KeyboardInterrupt):
+        backend.apply(plan)
+    assert not target.exists()
+
+
+def test_rollback_disables_timer_on_create_failure(tmp_path) -> None:
+    target = tmp_path / "schedls-backup.timer"
+
+    def systemctl(argv, _input):
+        if "daemon-reload" in argv:
+            return (1, "", "boom")
+        return ("", "")
+
+    runner = FakeRunner(handlers={"systemctl": systemctl}, available={"systemctl"})
+    backend = SystemdBackend(runner)
+    plan = Plan(backend="systemd", action="create")
+    plan.files = [FileChange(str(target), "content", mode=0o600)]
+    plan.commands = [CommandPlan(("systemctl", "daemon-reload"), "reload")]
+    plan.payload = {"scope": Scope.USER, "timer_unit": "schedls-backup.timer", "snapshots": {}}
+    with pytest.raises(OperationalError):
+        backend.apply(plan)
+    assert any("disable" in call[0] for call in runner.calls)
+    assert not target.exists()
+
+
+def test_logs_rejects_unsafe_service_unit() -> None:
+    backend = SystemdBackend(FakeRunner(available={"journalctl"}))
+    job = _managed_job(service_unit="--output=json.service")
+    with pytest.raises(SafetyRefusalError):
+        backend.logs(job, lines=5, since=None)
+
+
+def test_logs_returns_journal_text() -> None:
+    runner = FakeRunner(
+        handlers={"journalctl": lambda argv, _input: ("hello\n", "")},
+        available={"journalctl"},
+    )
+    backend = SystemdBackend(runner)
+    assert backend.logs(_managed_job(), lines=5, since="2 hours ago") == "hello\n"
+    argv = runner.calls[0][0]
+    assert "--since" in argv and "--lines=5" in argv
+
+
+def test_prefix_named_unit_without_marker_is_unmanaged(tmp_path) -> None:
+    timer_path = tmp_path / "schedls-backup.timer"
+    timer_path.write_text("[Unit]\n[Timer]\nOnCalendar=*-*-* 02:00:00\n")
+
+    def systemctl(argv, _input):
+        if "is-system-running" in argv:
+            return ("running\n", "")
+        if "list-unit-files" in argv or "list-units" in argv:
+            return ("schedls-backup.timer enabled\n", "")
+        if "show" in argv:
+            unit = argv[argv.index("show") + 1]
+            if unit.endswith(".timer"):
+                return (f"Id={unit}\nLoadState=loaded\nFragmentPath={timer_path}\n", "")
+            return ("", "")
+        return ("", "")
+
+    runner = FakeRunner(handlers={"systemctl": systemctl}, available={"systemctl"})
+    jobs = SystemdBackend(runner).discover([Scope.USER])
+    assert len(jobs) == 1
+    assert jobs[0].managed is False
+    assert jobs[0].name == "schedls-backup"

tests/unit/test_output.py

@@ -0,0 +1,105 @@
+from __future__ import annotations
+
+import io
+import json
+from datetime import UTC, datetime
+
+from schedls.models import (
+    Backend,
+    Command,
+    CronDetails,
+    JobSource,
+    Schedule,
+    ScheduledJob,
+    ScheduleKind,
+    Scope,
+    SystemdDetails,
+)
+from schedls.output import Output, job_to_dict, jobs_document, sanitize_text
+
+
+def _systemd_job() -> ScheduledJob:
+    return ScheduledJob(
+        name="backup",
+        backend=Backend.SYSTEMD,
+        scope=Scope.USER,
+        managed=True,
+        enabled=True,
+        schedule=Schedule(ScheduleKind.CALENDAR, "*-*-* 02:00:00", ("*-*-* 02:00:00",)),
+        command=Command(argv=("/usr/local/bin/backup", "/srv/data")),
+        source=JobSource("systemd user timer", path="/home/u/.config/systemd/user/schedls-backup.timer"),
+        next_run=datetime(2026, 9, 25, 2, 0, tzinfo=UTC),
+        systemd=SystemdDetails(
+            timer_unit="schedls-backup.timer",
+            service_unit="schedls-backup.service",
+            persistent=True,
+        ),
+    )
+
+
+def _cron_job() -> ScheduledJob:
+    return ScheduledJob(
+        name="cron-3",
+        backend=Backend.CRON,
+        scope=Scope.USER,
+        managed=False,
+        enabled=None,
+        schedule=Schedule(ScheduleKind.CRON, "0 4 * * 0"),
+        command=Command(raw="/usr/local/bin/cleanup"),
+        source=JobSource("current user's crontab", line=3),
+        cron=CronDetails(expression="0 4 * * 0", line=3),
+    )
+
+
+def test_job_to_dict_systemd() -> None:
+    data = job_to_dict(_systemd_job())
+    assert data["name"] == "backup"
+    assert data["backend"] == "systemd"
+    assert data["managed"] is True
+    assert data["next_run"].endswith("+00:00")
+    assert data["systemd"]["persistent"] is True
+
+
+def test_job_to_dict_cron_missing_data_is_null() -> None:
+    data = job_to_dict(_cron_job())
+    assert data["next_run"] is None
+    assert data["last_run"] is None
+    assert data["enabled"] is None
+
+
+def test_jobs_document_schema_and_no_ansi() -> None:
+    document = jobs_document([_systemd_job(), _cron_job()], ["a warning"])
+    assert document["schema_version"] == 1
+    assert len(document["jobs"]) == 2
+    dumped = json.dumps(document)
+    assert "\x1b" not in dumped
+    assert "backup" in dumped
+
+
+def test_output_table_and_key_values() -> None:
+    stream = io.StringIO()
+    output = Output(json_mode=False, color="never", stdout=stream)
+    output.table(["NAME", "BACKEND"], [["backup", "systemd"], ["cleanup", "cron"]])
+    text = stream.getvalue()
+    assert "NAME" in text
+    assert "backup" in text
+    assert "\x1b" not in text
+
+
+def test_output_json_mode() -> None:
+    stream = io.StringIO()
+    output = Output(json_mode=True, color="never", stdout=stream)
+    output.emit_json({"schema_version": 1, "jobs": []})
+    assert json.loads(stream.getvalue())["schema_version"] == 1
+
+
+def test_sanitize_text_escapes_control_characters() -> None:
+    text = "a\x1b[31mred\x1b[0m\nb\tc\x00d\x7f"
+    assert sanitize_text(text) == "a\\x1b[31mred\\x1b[0m\nb\tc\\x00d\\x7f"
+
+
+def test_output_write_is_verbatim() -> None:
+    stream = io.StringIO()
+    output = Output(color="never", stdout=stream)
+    output.write("line one\nline two")
+    assert stream.getvalue() == "line one\nline two"

tests/unit/test_prompt.py

@@ -0,0 +1,203 @@
+from __future__ import annotations
+
+import io
+
+import pytest
+
+from schedls.cli import _spec_for_edit, _spec_for_new, _wizard_edit, _wizard_new, build_parser
+from schedls.errors import ConfirmationRequiredError, InvalidScheduleError
+from schedls.models import (
+    Backend,
+    Command,
+    JobSource,
+    Schedule,
+    ScheduledJob,
+    ScheduleKind,
+    Scope,
+    SystemdDetails,
+)
+from schedls.output import Output
+from schedls.prompt import Prompter
+
+
+class FakeInput:
+    def __init__(self, answers: list[str]) -> None:
+        self.answers = list(answers)
+        self.prompts: list[str] = []
+
+    def __call__(self, label: str) -> str:
+        self.prompts.append(label)
+        if not self.answers:
+            raise EOFError
+        return self.answers.pop(0)
+
+
+class FakeStdin:
+    def __init__(self, *, isatty: bool) -> None:
+        self._isatty = isatty
+
+    def isatty(self) -> bool:
+        return self._isatty
+
+
+def make_prompter(answers: list[str], *, calendar_validator=None) -> tuple[Prompter, FakeInput]:
+    fake = FakeInput(answers)
+    output = Output(stdout=io.StringIO(), stderr=io.StringIO())
+    return Prompter(output=output, input_fn=fake, calendar_validator=calendar_validator), fake
+
+
+def _systemd_job() -> ScheduledJob:
+    return ScheduledJob(
+        name="backup",
+        backend=Backend.SYSTEMD,
+        scope=Scope.USER,
+        managed=True,
+        enabled=True,
+        schedule=Schedule(ScheduleKind.CALENDAR, "*-*-* 02:00:00"),
+        command=Command(argv=("/usr/local/bin/backup",)),
+        source=JobSource(detail="systemd user timer"),
+        systemd=SystemdDetails(on_calendar=("*-*-* 02:00:00",)),
+    )
+
+
+def test_text_requires_a_value() -> None:
+    prompter, fake = make_prompter(["", "backup"])
+    assert prompter.text("Name") == "backup"
+    assert len(fake.prompts) == 2
+
+
+def test_text_uses_default_on_blank() -> None:
+    prompter, _ = make_prompter([""])
+    assert prompter.text("Name", default="backup") == "backup"
+
+
+def test_optional_text() -> None:
+    prompter, _ = make_prompter(["", ""])
+    assert prompter.optional_text("Jitter") is None
+    assert prompter.optional_text("Jitter", default="5min") == "5min"
+
+
+def test_yes_no_rejects_unknown_answers() -> None:
+    prompter, _ = make_prompter(["maybe", "yes"])
+    assert prompter.yes_no("Continue?") is True
+
+
+def test_choice_by_number_and_default() -> None:
+    prompter, _ = make_prompter(["9", "2", ""])
+    options = [("daily", "Daily"), ("weekly", "Weekly")]
+    assert prompter.choice("Schedule:", options, default="daily") == "weekly"
+    assert prompter.choice("Schedule:", options, default="daily") == "daily"
+
+
+def test_command_builds_argv() -> None:
+    prompter, _ = make_prompter(["n", "/usr/bin/echo hello world"])
+    command = prompter.command()
+    assert command.shell is False
+    assert command.argv == ("/usr/bin/echo", "hello", "world")
+
+
+def test_command_shell_mode() -> None:
+    prompter, _ = make_prompter(["y", "echo hi | cat"])
+    command = prompter.command()
+    assert command.shell is True
+    assert command.raw == "echo hi | cat"
+
+
+def test_environment_collects_valid_entries() -> None:
+    prompter, _ = make_prompter(["A=1", "1BAD=2", "B=x=y", ""])
+    assert prompter.environment() == ["A=1", "B=x=y"]
+
+
+def test_schedule_daily_reprompts_on_bad_time() -> None:
+    prompter, _ = make_prompter(["", "25:00", "02:30"])
+    assert prompter.schedule(Backend.SYSTEMD) == {"daily": "02:30"}
+
+
+def test_schedule_weekly_and_monthly() -> None:
+    prompter, _ = make_prompter(["3", "Mon", "02:00"])
+    assert prompter.schedule(Backend.SYSTEMD) == {"weekly": ["Mon", "02:00"]}
+    prompter, _ = make_prompter(["4", "15", "06:00"])
+    assert prompter.schedule(Backend.SYSTEMD) == {"monthly": ["15", "06:00"]}
+
+
+def test_schedule_custom_systemd_validates() -> None:
+    def validator(expression: str) -> None:
+        if expression != "daily":
+            raise InvalidScheduleError("bad expression")
+
+    prompter, _ = make_prompter(["5", "bogus", "daily"], calendar_validator=validator)
+    assert prompter.schedule(Backend.SYSTEMD) == {"calendar": ["daily"]}
+
+
+def test_schedule_custom_cron() -> None:
+    prompter, _ = make_prompter(["5", "0 4 * * *"])
+    assert prompter.schedule(Backend.CRON) == {"cron_expr": "0 4 * * *"}
+
+
+def test_require_terminal_rejects_non_tty(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setattr("sys.stdin", FakeStdin(isatty=False))
+    prompter, _ = make_prompter([])
+    with pytest.raises(ConfirmationRequiredError):
+        prompter.require_terminal()
+
+
+def test_eof_raises_confirmation_required() -> None:
+    prompter, _ = make_prompter([])
+    with pytest.raises(ConfirmationRequiredError):
+        prompter.text("Name")
+
+
+def test_wizard_new_systemd(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setattr("sys.stdin", FakeStdin(isatty=True))
+    args = build_parser().parse_args(["new", "-i"])
+    answers = ["backup", "", "n", "/usr/local/bin/backup /srv/data", "", "02:00", "n"]
+    prompter, _ = make_prompter(answers)
+    args, tail = _wizard_new(args, [], prompter)
+    spec = _spec_for_new(args, tail)
+    assert spec.name == "backup"
+    assert spec.backend is Backend.SYSTEMD
+    assert spec.calendar == ("*-*-* 02:00:00",)
+    assert spec.command.argv == ("/usr/local/bin/backup", "/srv/data")
+
+
+def test_wizard_new_cron(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setattr("sys.stdin", FakeStdin(isatty=True))
+    args = build_parser().parse_args(["new", "-i"])
+    answers = ["cleanup", "2", "n", "/usr/local/bin/cleanup", "", "04:00"]
+    prompter, _ = make_prompter(answers)
+    args, tail = _wizard_new(args, [], prompter)
+    spec = _spec_for_new(args, tail)
+    assert spec.backend is Backend.CRON
+    assert spec.cron_expression == "0 4 * * *"
+
+
+def test_wizard_new_skips_provided_fields(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setattr("sys.stdin", FakeStdin(isatty=True))
+    args = build_parser().parse_args(["new", "backup", "-i", "--timer", "--daily", "02:00"])
+    prompter, fake = make_prompter(["n"])
+    args, tail = _wizard_new(args, ["/bin/true"], prompter)
+    spec = _spec_for_new(args, tail)
+    assert spec.calendar == ("*-*-* 02:00:00",)
+    assert fake.prompts == ["Set advanced timer options? [y/N] "]
+
+
+def test_wizard_edit_changes_schedule(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setattr("sys.stdin", FakeStdin(isatty=True))
+    job = _systemd_job()
+    args = build_parser().parse_args(["edit", "backup", "-i"])
+    answers = ["n", "y", "", "03:00", "n"]
+    prompter, _ = make_prompter(answers)
+    args, tail = _wizard_edit(job, args, [], prompter)
+    spec = _spec_for_edit(job, args, tail)
+    assert spec.calendar == ("*-*-* 03:00:00",)
+
+
+def test_wizard_edit_keeps_changes_optional(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setattr("sys.stdin", FakeStdin(isatty=True))
+    job = _systemd_job()
+    args = build_parser().parse_args(["edit", "backup", "-i"])
+    prompter, _ = make_prompter(["n", "n", "n"])
+    args, tail = _wizard_edit(job, args, [], prompter)
+    spec = _spec_for_edit(job, args, tail)
+    assert spec.calendar == ("*-*-* 02:00:00",)
+    assert tail == []

tests/unit/test_renderers_cron.py

@@ -0,0 +1,129 @@
+from __future__ import annotations
+
+import json
+import shlex
+import subprocess
+import sys
+
+import pytest
+
+from schedls.errors import InvalidScheduleError, SafetyRefusalError
+from schedls.models import Command
+from schedls.renderers import cron as renderer
+
+NASTY_ARGS = [
+    "plain",
+    "a b",
+    "a\tb",
+    'a"b',
+    "a'b",
+    "a\\b",
+    "a\\\\b",
+    "$HOME",
+    "$(touch /tmp/pwned)",
+    "`touch /tmp/pwned`",
+    "%",
+    "100%",
+    "a%b",
+    "a\\%b",
+    "a\\\\%b",
+    "",
+    " leading",
+    "trailing ",
+    "semi;colon",
+    "pipe|cmd",
+    "new&line",
+    ">out",
+    "unicode-\u00e9\u4e2d\U0001f600",
+]
+
+
+def cron_resolve(text: str) -> str:
+    """Emulate Cronie's ``%`` processing of a command field."""
+    out: list[str] = []
+    index = 0
+    while index < len(text):
+        char = text[index]
+        if char == "\\" and index + 1 < len(text) and text[index + 1] == "%":
+            out.append("%")
+            index += 2
+            continue
+        if char == "%":
+            out.append("\n")
+            index += 1
+            continue
+        out.append(char)
+        index += 1
+    return "".join(out)
+
+
+def test_escape_percent() -> None:
+    assert renderer.escape_percent("100%") == "100\\%"
+    assert renderer.escape_percent("a\\%b") == "a\\\\%b"
+
+
+def test_render_command_argv() -> None:
+    rendered = renderer.render_command(Command(argv=("/usr/local/bin/backup", "/srv/My Data")))
+    assert rendered == "/usr/local/bin/backup '/srv/My Data'"
+
+
+def test_render_command_shell() -> None:
+    rendered = renderer.render_command(Command(shell=True, raw="echo 50% > /tmp/x"))
+    assert rendered == "echo 50\\% > /tmp/x"
+
+
+def test_expression_percent_not_double_escaped() -> None:
+    line = renderer.render_line("0 2 * * *", Command(argv=("/bin/echo", "a%b")))
+    assert line == "0 2 * * * /bin/echo a\\%b"
+
+
+@pytest.mark.parametrize(
+    "bad",
+    ["", "0 2 * *", "0 2 * * * *", "60 2 * * *", "0 25 * * *", "0 2 32 * *", "@bogus", "a b c d e"],
+)
+def test_invalid_expressions(bad: str) -> None:
+    with pytest.raises(InvalidScheduleError):
+        renderer.validate_expression(bad)
+
+
+@pytest.mark.parametrize(
+    "good",
+    ["* * * * *", "0 2 * * *", "*/5 * * * *", "0 2 * * 1-5", "0 2 1,15 * 5", "@daily", "@reboot"],
+)
+def test_valid_expressions(good: str) -> None:
+    assert renderer.validate_expression(good)
+
+
+@pytest.mark.parametrize("arg", NASTY_ARGS)
+def test_argv_round_trip_through_shell(tmp_path, arg: str) -> None:
+    dump = tmp_path / "dump.py"
+    dump.write_text("import json,sys\nopen(sys.argv[1],'w').write(json.dumps(sys.argv[2:]))\n")
+    out = tmp_path / "out.json"
+    command = Command(argv=(sys.executable, str(dump), str(out), arg))
+    serialized = renderer.render_command(command)
+    resolved = cron_resolve(serialized)
+    subprocess.run(["/bin/sh", "-c", resolved], check=True)
+    received = json.loads(out.read_text())
+    assert received == [arg]
+
+
+def test_no_command_injection(tmp_path) -> None:
+    marker = tmp_path / "pwned"
+    command = Command(argv=("/bin/true", f"x; touch {marker}", f"$(touch {marker})", f"`touch {marker}`"))
+    resolved = cron_resolve(renderer.render_command(command))
+    subprocess.run(["/bin/sh", "-c", resolved], check=True)
+    assert not marker.exists()
+
+
+def test_newline_rejected() -> None:
+    with pytest.raises(SafetyRefusalError):
+        renderer.render_command(Command(argv=("/bin/echo", "a\nb")))
+
+
+def test_managed_block() -> None:
+    block = renderer.render_block("backup", ["0 2 * * * /bin/true"])
+    assert block == ("# schedls:begin name=backup\n0 2 * * * /bin/true\n# schedls:end name=backup\n")
+
+
+def test_shlex_reference() -> None:
+    assert shlex.quote("a b") == "'a b'"

tests/unit/test_renderers_systemd.py

@@ -0,0 +1,111 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+
+from schedls.errors import SafetyRefusalError
+from schedls.models import Backend, Command, JobSpec, Scope
+from schedls.renderers import systemd as renderer
+
+FIXTURES = Path(__file__).resolve().parents[1] / "fixtures" / "systemd"
+
+NASTY_ARGS = [
+    "plain",
+    "a b",
+    "a\tb",
+    'a"b',
+    "a'b",
+    "a\\b",
+    "a\\\\b",
+    "$HOME",
+    "$$",
+    "$(touch /tmp/pwned)",
+    "`touch /tmp/pwned`",
+    "%n",
+    "%%",
+    "%i",
+    "",
+    " leading",
+    "trailing ",
+    "semi;colon",
+    "pipe|cmd",
+    "new&line",
+    "unicode-\u00e9\u4e2d\U0001f600",
+    "-dash",
+    "@at",
+    "!bang",
+]
+
+
+def test_quote_basic() -> None:
+    assert renderer.quote_systemd_arg("plain") == '"plain"'
+    assert renderer.quote_systemd_arg("a b") == '"a b"'
+    assert renderer.quote_systemd_arg("") == '""'
+    assert renderer.quote_systemd_arg("$HOME") == '"$$HOME"'
+    assert renderer.quote_systemd_arg("%n") == '"%%n"'
+    assert renderer.quote_systemd_arg('a"b') == '"a\\"b"'
+    assert renderer.quote_systemd_arg("a\\b") == '"a\\\\b"'
+
+
+@pytest.mark.parametrize("arg", NASTY_ARGS)
+def test_argv_round_trip(arg: str) -> None:
+    command = Command(argv=(arg,))
+    rendered = renderer.render_exec_start(command)
+    value = rendered.split("=", 1)[1]
+    parsed = renderer.parse_exec_start(value)
+    assert parsed.argv == (arg,)
+
+
+def test_multi_argv_round_trip() -> None:
+    command = Command(argv=tuple(NASTY_ARGS))
+    value = renderer.render_exec_start(command).split("=", 1)[1]
+    assert renderer.parse_exec_start(value).argv == tuple(NASTY_ARGS)
+
+
+def test_shell_mode_round_trip() -> None:
+    command = Command(shell=True, raw="generate-report | gzip > /srv/report.gz")
+    value = renderer.render_exec_start(command).split("=", 1)[1]
+    parsed = renderer.parse_exec_start(value)
+    assert parsed.shell is True
+    assert parsed.raw == "generate-report | gzip > /srv/report.gz"
+
+
+def test_shell_mode_quotes_script() -> None:
+    command = Command(shell=True, raw="echo $HOME > /tmp/x")
+    rendered = renderer.render_exec_start(command)
+    assert rendered.startswith('ExecStart=/bin/sh -c "')
+    assert "$$HOME" in rendered
+
+
+@pytest.mark.parametrize("bad", ["a\nb", "a\rb", "a\x00b"])
+def test_control_characters_rejected(bad: str) -> None:
+    with pytest.raises(SafetyRefusalError):
+        renderer.render_exec_start(Command(argv=(bad,)))
+
+
+def test_golden_service() -> None:
+    spec = JobSpec(
+        name="backup",
+        backend=Backend.SYSTEMD,
+        scope=Scope.USER,
+        command=Command(argv=("/usr/local/bin/backup", "/srv/data")),
+        calendar=("*-*-* 02:00:00",),
+        persistent=True,
+    )
+    files = renderer.render_units(spec, service_unit="schedls-backup.service", timer_unit="schedls-backup.timer")
+    assert files["schedls-backup.service"] == (FIXTURES / "basic.service").read_text()
+    assert files["schedls-backup.timer"] == (FIXTURES / "basic.timer").read_text()
+
+
+def test_timer_multiple_calendars() -> None:
+    spec = JobSpec(
+        name="multi",
+        backend=Backend.SYSTEMD,
+        scope=Scope.USER,
+        command=Command(argv=("/bin/true",)),
+        calendar=("Mon..Fri 02:00:00", "Sat,Sun 04:00:00"),
+    )
+    timer = renderer.render_timer(spec, "schedls-multi.timer", "schedls-multi.service")
+    assert "OnCalendar=Mon..Fri 02:00:00" in timer
+    assert "OnCalendar=Sat,Sun 04:00:00" in timer

tests/unit/test_security.py

@@ -0,0 +1,175 @@
+from __future__ import annotations
+
+import os
+import stat
+
+import pytest
+
+from schedls.errors import InvalidNameError, SafetyRefusalError
+from schedls.runner import CommandRunner
+from schedls.security import (
+    atomic_write_text,
+    check_replaceable,
+    check_trusted_directory,
+    is_managed_unit,
+    is_safe_unit_name,
+    remove_file,
+    resolve_helper,
+    unit_name,
+    validate_managed_unit_name,
+    validate_name,
+)
+
+
+@pytest.mark.parametrize(
+    "name",
+    ["backup", "postgres-backup", "report.daily", "sync_home", "a", "A1._-", "x" * 64],
+)
+def test_valid_names(name: str) -> None:
+    assert validate_name(name) == name
+
+
+@pytest.mark.parametrize(
+    "name",
+    ["", "../foo", "foo/bar", "name with spaces", "$(command)", ".hidden", "-lead", "x" * 65, "foo\nbar", "foo\n"],
+)
+def test_invalid_names(name: str) -> None:
+    with pytest.raises(InvalidNameError):
+        validate_name(name)
+
+
+def test_unit_name() -> None:
+    assert unit_name("backup", "timer") == "schedls-backup.timer"
+    assert is_managed_unit("schedls-backup.timer")
+    assert not is_managed_unit("certbot.timer")
+    with pytest.raises(InvalidNameError):
+        unit_name("../evil", "timer")
+
+
+def test_atomic_write_and_remove(tmp_path) -> None:
+    target = tmp_path / "file.txt"
+    atomic_write_text(str(target), "hello\n", mode=0o600)
+    assert target.read_text() == "hello\n"
+    assert stat.S_IMODE(target.stat().st_mode) == 0o600
+    assert remove_file(str(target)) is True
+    assert not target.exists()
+    assert remove_file(str(target)) is False
+
+
+def test_atomic_write_refuses_symlink(tmp_path) -> None:
+    real = tmp_path / "real.txt"
+    real.write_text("secret")
+    link = tmp_path / "link.txt"
+    link.symlink_to(real)
+    with pytest.raises(SafetyRefusalError):
+        atomic_write_text(str(link), "overwrite")
+    assert real.read_text() == "secret"
+
+
+def test_remove_refuses_symlink(tmp_path) -> None:
+    real = tmp_path / "real.txt"
+    real.write_text("secret")
+    link = tmp_path / "link.txt"
+    link.symlink_to(real)
+    with pytest.raises(SafetyRefusalError):
+        remove_file(str(link))
+
+
+def test_check_replaceable_ownership(tmp_path) -> None:
+    target = tmp_path / "file.txt"
+    target.write_text("x")
+    check_replaceable(str(target), expected_uid=os.getuid())
+    with pytest.raises(SafetyRefusalError):
+        check_replaceable(str(target), expected_uid=os.getuid() + 99999)
+
+
+def test_resolve_helper_rejects_missing() -> None:
+    assert resolve_helper("definitely-not-a-real-helper-xyz") is None
+
+
+def test_resolve_helper_rejects_world_writable_dir(tmp_path, monkeypatch) -> None:
+    helper_dir = tmp_path / "bin"
+    helper_dir.mkdir()
+    helper = helper_dir / "evilhelper"
+    helper.write_text("#!/bin/sh\ntrue\n")
+    helper.chmod(0o755)
+    helper_dir.chmod(0o777)
+    monkeypatch.setenv("PATH", str(helper_dir))
+    assert resolve_helper("evilhelper") is None
+
+
+def test_resolve_helper_rejects_group_writable_file(tmp_path, monkeypatch) -> None:
+    helper_dir = tmp_path / "bin"
+    helper_dir.mkdir()
+    helper = helper_dir / "evilhelper"
+    helper.write_text("#!/bin/sh\ntrue\n")
+    helper.chmod(0o775)
+    monkeypatch.setenv("PATH", str(helper_dir))
+    assert resolve_helper("evilhelper") is None
+
+
+def test_resolve_helper_rejects_user_owned_dir_when_root(tmp_path, monkeypatch) -> None:
+    helper_dir = tmp_path / "bin"
+    helper_dir.mkdir()
+    helper = helper_dir / "evilhelper"
+    helper.write_text("#!/bin/sh\ntrue\n")
+    helper.chmod(0o755)
+    monkeypatch.setenv("PATH", str(helper_dir))
+    monkeypatch.setattr(os, "geteuid", lambda: 0)
+    assert resolve_helper("evilhelper") is None
+
+
+def test_resolve_helper_accepts_own_dir_when_not_root(tmp_path, monkeypatch) -> None:
+    helper_dir = tmp_path / "bin"
+    helper_dir.mkdir()
+    helper = helper_dir / "goodhelper"
+    helper.write_text("#!/bin/sh\ntrue\n")
+    helper.chmod(0o755)
+    monkeypatch.setenv("PATH", str(helper_dir))
+    monkeypatch.setattr(os, "geteuid", lambda: 4242)
+    assert resolve_helper("goodhelper") == str(helper)
+
+
+def test_runner_refuses_untrusted_absolute_helper(tmp_path, monkeypatch) -> None:
+    helper = tmp_path / "evil"
+    helper.write_text("#!/bin/sh\ntrue\n")
+    helper.chmod(0o755)
+    monkeypatch.setattr(os, "geteuid", lambda: 0)
+    with pytest.raises(SafetyRefusalError):
+        CommandRunner().run([str(helper)])
+
+
+def test_runner_refuses_relative_executable() -> None:
+    with pytest.raises(SafetyRefusalError):
+        CommandRunner().run(["bin/evil"])
+
+
+def test_check_trusted_directory_owner_and_mode(tmp_path) -> None:
+    check_trusted_directory(str(tmp_path), expected_uid=os.getuid())
+    with pytest.raises(SafetyRefusalError):
+        check_trusted_directory(str(tmp_path), expected_uid=os.getuid() + 99999)
+    tmp_path.chmod(0o777)
+    with pytest.raises(SafetyRefusalError):
+        check_trusted_directory(str(tmp_path), expected_uid=os.getuid())
+
+
+def test_validate_managed_unit_name() -> None:
+    assert validate_managed_unit_name("schedls-backup.timer") == "schedls-backup.timer"
+    assert validate_managed_unit_name("schedls-a_b.service") == "schedls-a_b.service"
+    for unit in (
+        "../../etc/passwd",
+        "schedls-../x.timer",
+        "certbot.timer",
+        "schedls-x.timer/../y",
+        "schedls-x.timer\n",
+    ):
+        with pytest.raises(SafetyRefusalError):
+            validate_managed_unit_name(unit)
+
+
+def test_is_safe_unit_name() -> None:
+    assert is_safe_unit_name("certbot.service")
+    assert is_safe_unit_name("foo@bar.timer")
+    assert not is_safe_unit_name("--output=json")
+    assert not is_safe_unit_name("../../evil.service")
+    assert not is_safe_unit_name("unit with spaces.service")

tests/unit/test_timefmt.py

@@ -0,0 +1,69 @@
+from __future__ import annotations
+
+from datetime import UTC, datetime, timedelta, timezone
+
+import pytest
+
+from schedls import timefmt
+
+
+@pytest.mark.parametrize(
+    ("value", "seconds"),
+    [
+        ("1s", 1.0),
+        ("30m", 1800.0),
+        ("1h", 3600.0),
+        ("2h30m", 9000.0),
+        ("1d", 86400.0),
+        ("1w", 604800.0),
+        ("500ms", 0.5),
+        ("1min", 60.0),
+    ],
+)
+def test_duration_seconds(value: str, seconds: float) -> None:
+    assert timefmt.duration_seconds(value) == pytest.approx(seconds)
+
+
+@pytest.mark.parametrize("bad", ["", "abc", "1x", "h", "1h2x"])
+def test_invalid_duration(bad: str) -> None:
+    with pytest.raises(ValueError):
+        timefmt.duration_seconds(bad)
+    assert not timefmt.is_valid_duration(bad)
+
+
+def test_parse_microseconds() -> None:
+    parsed = timefmt.parse_systemd_timestamp("1758700800000000")
+    assert parsed is not None
+    assert parsed.year == 2025
+
+
+def test_parse_pretty() -> None:
+    parsed = timefmt.parse_systemd_timestamp("Thu 2026-09-24 06:49:28 BST")
+    assert parsed is not None
+    assert (parsed.year, parsed.month, parsed.day) == (2026, 9, 24)
+    assert parsed.tzinfo is not None
+
+
+def test_parse_placeholders() -> None:
+    assert timefmt.parse_systemd_timestamp("") is None
+    assert timefmt.parse_systemd_timestamp("n/a") is None
+    assert timefmt.parse_systemd_timestamp("0") is None
+
+
+def test_format_datetime_round_trip_zone() -> None:
+    dt = datetime(2026, 9, 25, 2, 0, 0, tzinfo=timezone(timedelta(hours=1)))
+    text = timefmt.format_datetime(dt)
+    assert text.startswith("Fri 25 Sep 2026 02:00:00")
+
+
+def test_format_short_relative() -> None:
+    now = datetime(2026, 9, 24, 12, 0, tzinfo=UTC)
+    today = datetime(2026, 9, 24, 18, 0, tzinfo=UTC)
+    tomorrow = datetime(2026, 9, 25, 3, 0, tzinfo=UTC)
+    assert timefmt.format_short(today, now=now, utc=True) == "today 18:00"
+    assert timefmt.format_short(tomorrow, now=now, utc=True) == "tomorrow 03:00"
+
+
+def test_isoformat_has_offset() -> None:
+    dt = datetime(2026, 9, 25, 2, 0, tzinfo=UTC)
+    assert timefmt.isoformat(dt).endswith("+00:00")