## root / test / hs / Test / Ganeti / Locking / Allocation.hs @ 9bf17b50

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{-# LANGUAGE TemplateHaskell #-} |
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{-# OPTIONS_GHC -fno-warn-orphans #-} |

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{-| Tests for lock allocation. |

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-} |

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{- |

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Copyright (C) 2014 Google Inc. |

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This program is free software; you can redistribute it and/or modify |

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it under the terms of the GNU General Public License as published by |

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the Free Software Foundation; either version 2 of the License, or |

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(at your option) any later version. |

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This program is distributed in the hope that it will be useful, but |

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WITHOUT ANY WARRANTY; without even the implied warranty of |

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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |

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General Public License for more details. |

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You should have received a copy of the GNU General Public License |

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along with this program; if not, write to the Free Software |

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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |

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02110-1301, USA. |

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-} |

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module Test.Ganeti.Locking.Allocation (testLocking_Allocation) where |

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import Control.Applicative |

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import qualified Data.Foldable as F |

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import qualified Data.Map as M |

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import qualified Data.Set as S |

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import Test.QuickCheck |

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import Test.Ganeti.TestCommon |

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import Test.Ganeti.TestHelper |

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import Ganeti.BasicTypes |

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import Ganeti.Locking.Allocation |

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import Ganeti.Locking.Types |

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{- |

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Ganeti.Locking.Allocation is polymorphic in the types of locks |

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and lock owners. So we can use much simpler types here than Ganeti's |

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real locks and lock owners, knowning at polymorphic functions cannot |

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exploit the simplicity of the types they're deling with. |

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-} |

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data TestOwner = TestOwner Int deriving (Ord, Eq, Show) |

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instance Arbitrary TestOwner where |

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arbitrary = TestOwner <$> choose (0, 2) |

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data TestLock = TestBigLock |

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| TestCollectionLockA |

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| TestLockA Int |

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| TestCollectionLockB |

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| TestLockB Int |

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deriving (Ord, Eq, Show) |

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instance Arbitrary TestLock where |

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arbitrary = frequency [ (1, elements [ TestBigLock |

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, TestCollectionLockA |

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, TestCollectionLockB |

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]) |

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, (2, TestLockA <$> choose (0, 2)) |

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, (2, TestLockB <$> choose (0, 2)) |

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] |

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instance Lock TestLock where |

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lockImplications (TestLockA _) = [TestCollectionLockA, TestBigLock] |

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lockImplications (TestLockB _) = [TestCollectionLockB, TestBigLock] |

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lockImplications TestBigLock = [] |

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lockImplications _ = [TestBigLock] |

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{- |

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All states of a LockAllocation can be obtained by starting from the |

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empty allocation, and sequentially requesting (successfully or not) |

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lock updates. So we first define what arbitrary updates sequences are. |

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-} |

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instance Arbitrary OwnerState where |

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arbitrary = elements [OwnShared, OwnExclusive] |

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instance Arbitrary a => Arbitrary (LockRequest a) where |

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arbitrary = LockRequest <$> arbitrary <*> genMaybe arbitrary |

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data UpdateRequest a b = UpdateRequest a [LockRequest b] deriving Show |

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instance (Arbitrary a, Arbitrary b) => Arbitrary (UpdateRequest a b) where |

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arbitrary = UpdateRequest <$> arbitrary <*> arbitrary |

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-- | Fold a sequence of update requests; all allocations can be obtained in |

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-- this way, starting from the empty allocation. |

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foldUpdates :: (Lock a, Ord b, Show b) |

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=> LockAllocation a b -> [UpdateRequest b a] -> LockAllocation a b |

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foldUpdates = foldl (\s (UpdateRequest owner updates) -> |

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fst $ updateLocks owner updates s) |

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instance (Arbitrary a, Lock a, Arbitrary b, Ord b, Show b) |

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=> Arbitrary (LockAllocation a b) where |

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arbitrary = foldUpdates emptyAllocation <$> arbitrary |

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-- | Basic property of locking: the exclusive locks of one user |

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-- are disjoint from any locks of any other user. |

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prop_LocksDisjoint :: Property |

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prop_LocksDisjoint = |

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forAll (arbitrary :: Gen (LockAllocation TestLock TestOwner)) $ \state -> |

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forAll (arbitrary :: Gen TestOwner) $ \a -> |

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forAll (arbitrary `suchThat` (/= a)) $ \b -> |

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let aExclusive = M.keysSet . M.filter (== OwnExclusive) $ listLocks a state |

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bAll = M.keysSet $ listLocks b state |

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in printTestCase |

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(show a ++ "'s exclusive lock" ++ " is not respected by " ++ show b) |

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(S.null $ S.intersection aExclusive bAll) |

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-- | Verify that locks can only be modified by updates of the owner. |

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prop_LocksStable :: Property |

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prop_LocksStable = |

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forAll (arbitrary :: Gen (LockAllocation TestLock TestOwner)) $ \state -> |

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forAll (arbitrary :: Gen TestOwner) $ \a -> |

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forAll (arbitrary `suchThat` (/= a)) $ \b -> |

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forAll (arbitrary :: Gen [LockRequest TestLock]) $ \request -> |

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let (state', _) = updateLocks b request state |

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in (listLocks a state ==? listLocks a state') |

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-- | Verify that a given request is statisfied in list of owned locks |

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requestSucceeded :: Ord a => M.Map a OwnerState -> LockRequest a -> Bool |

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requestSucceeded owned (LockRequest lock status) = M.lookup lock owned == status |

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-- | Verify that lock updates are atomic, i.e., either we get all the required |

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-- locks, or the state is completely unchanged. |

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prop_LockupdateAtomic :: Property |

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prop_LockupdateAtomic = |

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forAll (arbitrary :: Gen (LockAllocation TestLock TestOwner)) $ \state -> |

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forAll (arbitrary :: Gen TestOwner) $ \a -> |

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forAll (arbitrary :: Gen [LockRequest TestLock]) $ \request -> |

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let (state', result) = updateLocks a request state |

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in if result == Ok S.empty |

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then printTestCase |

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("Update succeeded, but in final state " ++ show state' |

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++ "not all locks are as requested") |

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$ let owned = listLocks a state' |

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in all (requestSucceeded owned) request |

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else printTestCase |

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("Update failed, but state changed to " ++ show state') |

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(state == state') |

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-- | Verify that releasing a lock always succeeds. |

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prop_LockReleaseSucceeds :: Property |

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prop_LockReleaseSucceeds = |

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forAll (arbitrary :: Gen (LockAllocation TestLock TestOwner)) $ \state -> |

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forAll (arbitrary :: Gen TestOwner) $ \a -> |

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forAll (arbitrary :: Gen TestLock) $ \lock -> |

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let (_, result) = updateLocks a [requestRelease lock] state |

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in printTestCase |

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("Releasing a lock has to suceed uncondiationally, but got " |

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++ show result) |

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(isOk result) |

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-- | Verify the property that only the blocking owners prevent |

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-- lock allocation. We deliberatly go for the expensive variant |

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-- restraining by suchThat, as otherwise the number of cases actually |

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-- covered is too small. |

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prop_BlockSufficient :: Property |

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prop_BlockSufficient = |

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forAll (arbitrary :: Gen TestOwner) $ \a -> |

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forAll (arbitrary :: Gen TestLock) $ \lock -> |

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forAll (elements [ [requestShared lock] |

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, [requestExclusive lock]]) $ \request -> |

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forAll ((arbitrary :: Gen (LockAllocation TestLock TestOwner)) |

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`suchThat` (genericResult (const False) (not . S.null) |

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. snd . updateLocks a request)) $ \state -> |

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let (_, result) = updateLocks a request state |

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blockedOn = genericResult (const S.empty) id result |

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in printTestCase "After all blockers release, a request must succeed" |

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. isOk . snd . updateLocks a request $ F.foldl freeLocks state blockedOn |

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testSuite "Locking/Allocation" |

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[ 'prop_LocksDisjoint |

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, 'prop_LocksStable |

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, 'prop_LockupdateAtomic |

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, 'prop_LockReleaseSucceeds |

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, 'prop_BlockSufficient |

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] |