From 188593ed4e5772524b2c151f560d9c1339b57b67 Mon Sep 17 00:00:00 2001
From: Jean-Paul Calderone <exarkun@twistedmatrix.com>
Date: Mon, 16 Dec 2019 10:54:31 -0500
Subject: [PATCH] A couple simple starter tests for lease maintenance
---
src/_zkapauthorizer/lease_maintenance.py | 27 +++++---
src/_zkapauthorizer/tests/matchers.py | 21 +++++++
.../tests/test_lease_maintenance.py | 61 +++++++++++++++++--
3 files changed, 96 insertions(+), 13 deletions(-)
diff --git a/src/_zkapauthorizer/lease_maintenance.py b/src/_zkapauthorizer/lease_maintenance.py
index 3101909..ea4e920 100644
--- a/src/_zkapauthorizer/lease_maintenance.py
+++ b/src/_zkapauthorizer/lease_maintenance.py
@@ -268,6 +268,8 @@ def lease_maintenance_service(
secret_holder,
last_run,
random,
+ interval_mean=None,
+ interval_range=None,
):
"""
Get an ``IService`` which will maintain leases on ``root_node`` and any
@@ -293,15 +295,26 @@ def lease_maintenance_service(
:param random: An object like ``random.Random`` which can be used as a
source of scheduling delay.
+
+ :param timedelta interval_mean: The mean time between lease renewal checks.
+
+ :param timedelta interval_range: The range of the uniform distribution of
+ lease renewal checks (centered on ``interval_mean``).
"""
- mean = timedelta(days=26).total_seconds()
- halfrange = timedelta(days=2).total_seconds()
+ if interval_mean is None:
+ interval_mean = timedelta(days=26)
+ if interval_range is None:
+ interval_range = timedelta(days=4)
+ halfrange = interval_range / 2
+
min_lease_remaining = timedelta(days=3)
- sample_interval_distribution = partial(
- random.uniform,
- mean - halfrange,
- mean + halfrange,
- )
+ def sample_interval_distribution():
+ return timedelta(
+ seconds=random.uniform(
+ (interval_mean - halfrange).total_seconds(),
+ (interval_mean + halfrange).total_seconds(),
+ ),
+ )
if last_run is None:
initial_interval = sample_interval_distribution()
else:
diff --git a/src/_zkapauthorizer/tests/matchers.py b/src/_zkapauthorizer/tests/matchers.py
index bcb4edb..0a52380 100644
--- a/src/_zkapauthorizer/tests/matchers.py
+++ b/src/_zkapauthorizer/tests/matchers.py
@@ -23,6 +23,11 @@ from testtools.matchers import (
Mismatch,
ContainsDict,
Always,
+ MatchesAll,
+ MatchesAny,
+ GreaterThan,
+ LessThan,
+ Equals,
)
@attr.s
@@ -78,3 +83,19 @@ class _Returns(Matcher):
def __str__(self):
return "Returns({})".format(self.result_matcher)
+
+
+def between(low, high):
+ """
+ Matches a value in the range [low, high].
+ """
+ return MatchesAll(
+ MatchesAny(
+ Equals(low),
+ GreaterThan(low),
+ ),
+ MatchesAny(
+ Equals(high),
+ LessThan(high),
+ ),
+ )
diff --git a/src/_zkapauthorizer/tests/test_lease_maintenance.py b/src/_zkapauthorizer/tests/test_lease_maintenance.py
index b559dfd..5718c8b 100644
--- a/src/_zkapauthorizer/tests/test_lease_maintenance.py
+++ b/src/_zkapauthorizer/tests/test_lease_maintenance.py
@@ -22,7 +22,7 @@ from __future__ import (
)
from datetime import (
- datetime,
+ # datetime,
timedelta,
)
@@ -31,12 +31,17 @@ import attr
from testtools import (
TestCase,
)
+from hypothesis import (
+ given,
+)
from hypothesis.strategies import (
builds,
binary,
integers,
lists,
+ floats,
dictionaries,
+ randoms,
)
from twisted.internet.task import (
@@ -62,12 +67,13 @@ from ..foolscap import (
from .matchers import (
Provides,
+ between,
)
from .strategies import (
storage_indexes,
)
-from ..lease_maintenace import (
+from ..lease_maintenance import (
lease_maintenance_service,
)
@@ -140,13 +146,13 @@ class LeaseMaintenanceServiceTests(TestCase):
"""
Tests for the service returned by ``lease_maintenance_service``.
"""
- def test_interface(self):
+ @given(randoms())
+ def test_interface(self, random):
"""
The service provides ``IService``.
"""
clock = Clock()
root_node = object()
- random = object()
lease_secret = b"\0" * CRYPTO_VAL_SIZE
convergence_secret = b"\1" * CRYPTO_VAL_SIZE
service = lease_maintenance_service(
@@ -154,10 +160,53 @@ class LeaseMaintenanceServiceTests(TestCase):
root_node,
DummyStorageBroker(clock, []),
SecretHolder(lease_secret, convergence_secret),
- datetime.utcfromtimestamp(0),
+ None,
random,
)
self.assertThat(
service,
- Provides(IService),
+ Provides([IService]),
+ )
+
+ @given(
+ randoms(),
+ floats(
+ # It doesn't make sense to have a negative check interval mean.
+ min_value=0,
+ # We can't make this value too large or it isn't convertable to a
+ # timedelta. Also, even values as large as this one are of
+ # questionable value.
+ max_value=60 * 60 * 24 * 365),
+ )
+ def test_initial_interval(self, random, mean):
+ """
+ When constructed without a value for ``last_run``,
+ ``lease_maintenance_service`` schedules its first run to take place
+ after an interval that falls uniformly in range centered on ``mean``
+ with a size of ``range``.
+ """
+ clock = Clock()
+ root_node = object()
+ lease_secret = b"\0" * CRYPTO_VAL_SIZE
+ convergence_secret = b"\1" * CRYPTO_VAL_SIZE
+
+ # Construct a range that fits in with the mean
+ range_ = random.uniform(0, mean)
+
+ service = lease_maintenance_service(
+ clock,
+ root_node,
+ DummyStorageBroker(clock, []),
+ SecretHolder(lease_secret, convergence_secret),
+ None,
+ random,
+ timedelta(seconds=mean),
+ timedelta(seconds=range_),
+ )
+ service.startService()
+
+ [maintenance_call] = clock.getDelayedCalls()
+ self.assertThat(
+ maintenance_call.getTime(),
+ between(mean - (range_ / 2), mean + (range_ / 2)),
)
--
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