public void Delete_ingAKeyFromASingleLevelSkiplistOtherThanTheHead_ShouldDeleteExactlyOneNode
(Skiplist <int> sut, List <int> keys)
{
// Fixture setup
var expectedResult = keys.Count - 1;
keys.Remove(sut.Head.Down.Key);
var key = keys.First();
// Exercise system
sut.Delete(key);
// Verify outcome
var result = sut.Head.Bottom().EnumerateRight().Count();
var failureString =
String.Format(
"Removing key {0} from skiplist \n\n{1}\n deleted other than exactly one node",
key,
sut);
Assert.True(result == expectedResult, failureString);
// Teardown
}
public void Delete_ingAKeyFromMinimallySizedGapWithNoGapToTheRight_ShouldCauseTheGapToMergeWithTheOneToTheLeft
(Skiplist <int> sut, List <int> keys)
{
// Fixture setup
var expectedResult = 3;
var key = keys.Max();
foreach (var node in sut.Head.Down.EnumerateRight())
{
node.Down.ConnectTo(node.Right.Down.Left);
}
// Exercise system
sut.Delete(key);
// Verify outcome
var result = sut.Head.Left.SizeOfGap();
var failureString =
String.Format(
"Removing key {0} from skiplist \n\n{1}\n did not cause the right gap to merge with the left gap",
key,
sut);
Assert.True(result == expectedResult, failureString);
// Teardown
}
public void Delete_ingAKeyFromAPairOfMinimallySizedGaps_ShouldCauseHeightOfTheSkiplistToDropByOne
(Skiplist <int> sut, List <int> keys)
{
// Fixture setup
var expectedResult = 1;
var key = keys.Min();
foreach (var node in sut.Head.Down.EnumerateRight())
{
node.Down.ConnectTo(node.Right.Down.Left);
}
// Exercise system
sut.Delete(key);
// Verify outcome
var result = sut.Head.Height();
var failureString =
String.Format(
"Removing key {0} from skiplist \n\n{1}\n did not cause the skiplist to drop in height by 1",
key,
sut);
Assert.True(result == expectedResult, failureString);
// Teardown
}
public void Delete_ingAKeyFromMinimallySizedGapWithAMoreThanMinimalGapToTheRight_ShouldCauseTheGapToBorrowFromTheOneToTheRight
(Skiplist <int> sut, List <int> keys)
{
// Fixture setup
var expectedResult = 2;
var key = keys.Min();
sut.Head.Down.Down.ConnectTo(sut.Head.Down.Right.Down.Left);
// Exercise system
sut.Delete(key);
// Verify outcome
var result = sut.Head.SizeOfGap();
var failureString =
String.Format(
"Removing key {0} from skiplist \n\n{1}\n did not cause the left gap to borrow from the right gap",
key,
sut);
Assert.True(result == expectedResult, failureString);
// Teardown
}
public void Delete_ingAKeyFromTheBaseOfAColumn_ShouldUpdateTheKeysInTheColumnToTheCorrectValue
(Skiplist <int> sut, List <int> keys)
{
// Fixture setup
var expectedKey = sut.Head.Bottom().Right.Key;
var key = keys.Min();
// Exercise system
sut.Delete(key);
// Verify outcome
var result = sut.Head.EnumerateDown().Where(node => node.Key != expectedKey).ToList();
var failureString =
String.Format(
"Removing key {0} from skiplist \n\n{1}\n did not update the keys in the column. Instead, nodes {2} remained",
key,
sut,
String.Join(", ", result));
Assert.False(result.Any(), failureString);
// Teardown
}
public void Delete_ingAKeyFromTheBaseOfAColumn_ShouldUpdateTheColumnToPointAtTheNodeToTheRight
(Skiplist <int> sut, List <int> keys)
{
// Fixture setup
var expectedResult = sut.Head.Bottom().Right;
var key = keys.Min();
// Exercise system
sut.Delete(key);
// Verify outcome
var result = sut.Head.Bottom();
var failureString =
String.Format(
"Removing key {0} from skiplist \n\n{1}\n did not update the column to point at node {2}",
key,
sut,
expectedResult);
Assert.True(result == expectedResult, failureString);
// Teardown
}
public void Delete_ingAKeyFromAnEmptySkiplist_ShouldReturnFalse
(Skiplist <int> sut, int key)
{
// Fixture setup
// Exercise system
var result = sut.Delete(key);
// Verify outcome
var failureString =
String.Format(
"Removing key {0} from skiplist \n\n{1}\n returned true despite the skiplist being empty",
key,
sut);
Assert.False(result, failureString);
// Teardown
}
public void Delete_ingTheKeyOfTheHeadOfASingleNodeSkiplist_ShouldLeaveSkiplistEmpty
(Skiplist <int> sut)
{
// Fixture setup
var key = sut.Head.Key;
// Exercise system
sut.Delete(key);
// Verify outcome
var result = sut.Head == null;
var failureString =
String.Format(
"Removing key {0} from single-node skiplist \n\n{1}\n left the head intact",
key,
sut);
Assert.True(result, failureString);
// Teardown
}
public void Delete_ingAKeyFromASingleLevelSkiplistOtherThanTheHead_ShouldDeleteANodeContainingThatKey
(Skiplist <int> sut, List <int> keys)
{
// Fixture setup
keys.Remove(sut.Head.Down.Key);
var key = keys.First();
// Exercise system
sut.Delete(key);
// Verify outcome
var result = sut.Head.Bottom().EnumerateRight().Any(node => node.Key == key);
var failureString =
String.Format(
"Removing key {0} from skiplist \n\n{1}\n did not Delete the node containing that key",
key,
sut);
Assert.False(result, failureString);
// Teardown
}
public void Delete_ingTheKeyOfTheHeadOfASingleLevelSkiplist_ShouldDeleteOnlyOneNode
(Skiplist <int> sut, List <int> keys)
{
// Fixture setup
var expectedResult = keys.Count - 1;
var key = sut.Head.Key;
// Exercise system
sut.Delete(key);
// Verify outcome
var result = sut.Head.Bottom().EnumerateRight().Count();
var failureString =
String.Format(
"Removing key {0} from skiplist \n\n{1}\n left other than one node intact",
key,
sut);
Assert.True(result == expectedResult, failureString);
// Teardown
}