BuildRandomLastWriteWinsElementSet(DateTime?start = null)
{
var elementSet = new LastWriteWinsElementSet <int>();
start = start ?? DateTime.Parse("2018-10-02");
const int operationCount = 1000;
var random = new Random();
var timestamp = start.Value;
for (int i = 0; i < operationCount; i++)
{
timestamp = timestamp.AddMilliseconds(random.Next(1, 10000));
var element = random.Next(1, 100);
if (elementSet.Lookup(element)) // Can be addition or removal
{
if (random.Next(1, 10) % 2 == 0)
{
elementSet.Add(element, timestamp);
}
else
{
elementSet.Remove(element, timestamp);
}
}
else
{
elementSet.Add(element, timestamp);
}
}
return(elementSet, timestamp);
}
public void TestAdditionAndRemoval()
{
var elementSet = new LastWriteWinsElementSet <int>();
var start = DateTime.Parse("2018-10-02");
// Initially, no element is in the set
elementSet.Lookup(3).Should().BeFalse();
// Adds element should show up in the set
elementSet.Add(3, start);
elementSet.Lookup(3).Should().BeTrue();
// Adds the same element again should not give error
elementSet.Add(3, start.AddSeconds(1));
elementSet.Lookup(3).Should().BeTrue();
// Removes the element should make the element disappear
elementSet.Remove(3, start.AddSeconds(2));
elementSet.Lookup(3).Should().BeFalse();
// Re-adds the element should make the element show up again
elementSet.Add(3, start.AddSeconds(4));
elementSet.Lookup(3).Should().BeTrue();
// Re-removes the element should make the element disappear again
elementSet.Remove(3, start.AddSeconds(5));
elementSet.Lookup(3).Should().BeFalse();
// Removes an element that doesn't exist should throw error
Assert.Throws <ArgumentException>(() => elementSet.Remove(4, start.AddSeconds(6)));
}
