public void LockManagerLockTest()
{
LockManager target = new LockManager();
int transId = 1;
int dataItem = 1;
List<int> actual = target.Lock(transId, dataItem, Enumerations.OperationMode.Read);
Assert.IsNull(actual);
transId = 2;
actual = target.Lock(transId, dataItem, Enumerations.OperationMode.Read);
Assert.IsNull(actual);
actual = target.Lock(transId, dataItem, Enumerations.OperationMode.Write);
Assert.AreEqual(1, actual[0]);
Assert.AreEqual(2, actual[1]);
dataItem = 2;
actual = target.Lock(transId, dataItem, Enumerations.OperationMode.Write);
Assert.IsNull(actual);
transId = 1;
actual = target.Lock(transId, dataItem, Enumerations.OperationMode.Read);
Assert.AreEqual(2, actual[0]);
}
public void LockConflictsTest()
{
LockManager target = new LockManager();
int transId = 1;
int dataItem = 1;
target.Lock(transId, dataItem, Enumerations.OperationMode.Read);
Lock test = new Lock(transId, Enumerations.OperationMode.Read);
// lock never conflicts with a lock from its own transaction
Assert.IsFalse(target.LockConflicts(test, target.lockEntries[dataItem]));
test = new Lock(transId, Enumerations.OperationMode.Write);
Assert.IsFalse(target.LockConflicts(test, target.lockEntries[dataItem]));
test = new Lock(2,Enumerations.OperationMode.Read);
// two read locks do not conflict
Assert.IsFalse(target.LockConflicts(test, target.lockEntries[dataItem]));
test = new Lock(2, Enumerations.OperationMode.Write);
// A read lock conflicts with a write lock
Assert.IsTrue(target.LockConflicts(test, target.lockEntries[dataItem]));
transId = dataItem = 2;
target.Lock(transId, dataItem, Enumerations.OperationMode.Write);
// lock never conflicts with a lock from its own transaction
Assert.IsFalse(target.LockConflicts(test, target.lockEntries[dataItem]));
test = new Lock(transId, Enumerations.OperationMode.Read);
Assert.IsFalse(target.LockConflicts(test, target.lockEntries[dataItem]));
// a write lock or read lock from another transaction always conflicts with an active write lock
transId = 1;
test = new Lock(transId, Enumerations.OperationMode.Read);
Assert.IsTrue(target.LockConflicts(test, target.lockEntries[dataItem]));
test = new Lock(transId, Enumerations.OperationMode.Write);
Assert.IsTrue(target.LockConflicts(test, target.lockEntries[dataItem]));
// reset everything and just test that a recovered lockmanager denies read locks until a write op comes in
target = new LockManager();
// mock up what happens in a recovery - this is covered in a unit test in Site
for (int i = 2; i <= 20; i += 2)
{
target.lockEntries[i] = new LockManagerTableEntry();
target.lockEntries[i].ActiveLocks.Add(new Lock(int.MinValue, Enumerations.OperationMode.Write));
}
// try to issue a read op
transId = 1;
dataItem = 2;
test = new Lock(transId, Enumerations.OperationMode.Read);
Assert.IsTrue(target.LockConflicts(test, target.lockEntries[dataItem]));
// issue a write op which will work
test = new Lock(transId, Enumerations.OperationMode.Write);
Assert.IsFalse(target.LockConflicts(test, target.lockEntries[dataItem]));
}