public void CompressionBasic()
{
// Create diff and two uncompressable changes
var diff = new Diff <int>();
var initialChange1 = new ValueChange <int>((1, 2), 0, 1);
var initialChange2 = new ValueChange <int>((5, 6), 0, 1);
diff.Add(initialChange1);
diff.Add(initialChange2);
Assert.Equal(2, diff.Changes.Count);
Assert.False(diff.IsCompressed);
// Compress (which should not remove either change since they're not to the same position);
// but it will mark the diff as fully compressed
diff.Compress();
Assert.Equal(2, diff.Changes.Count);
Assert.True(diff.IsCompressed);
// Add a compressable change
var change1TrueToFalse = new ValueChange <int>((1, 2), 1, 0);
diff.Add(change1TrueToFalse);
Assert.Equal(3, diff.Changes.Count);
Assert.False(diff.IsCompressed);
// Compress (which should remove one position entirely since the changes offset)
diff.Compress();
Assert.Single(diff.Changes);
Assert.True(diff.IsCompressed);
Assert.Equal(diff.Changes[0], initialChange2);
// Add a series of changes, 2 of which offset
var uniquePositionChange = new ValueChange <int>((20, 20), 0, 1);
var nonDuplicateForFirstPos = new ValueChange <int>((1, 2), 0, 2);
diff.Add(initialChange1);
diff.Add(uniquePositionChange);
diff.Add(change1TrueToFalse);
diff.Add(nonDuplicateForFirstPos);
Assert.Equal(5, diff.Changes.Count);
Assert.False(diff.IsCompressed);
// Compress, which should remove the two offsetting changes, keep the most recent one, but not necessarily
// preserve the relative ordering.
diff.Compress();
Assert.Equal(3, diff.Changes.Count);
Assert.Equal(
diff.Changes.ToHashSet(),
new HashSet <ValueChange <int> > {
initialChange2, uniquePositionChange, nonDuplicateForFirstPos
});
Assert.True(diff.IsCompressed);
}
public void CompressionProducesMinimalSet()
{
var rand = new Random();
// Create diff and add random changes that will have duplicates
var diff = new Diff <int>();
var positions = new Point[] { (1, 2), (5, 6), (20, 21) };
var currentValues = new Dictionary <Point, int>();
for (int i = 0; i < 100; i++)
{
foreach (var pos in positions)
{
int oldVal = currentValues.GetValueOrDefault(pos);
int newVal;
do
{
newVal = rand.Next(1, 6);
} while (oldVal == newVal);
diff.Add(new ValueChange <int>(pos, oldVal, newVal));
currentValues[pos] = newVal;
}
}
Assert.Equal(100 * positions.Length, diff.Changes.Count);
Assert.False(diff.IsCompressed);
// We know what the current values are; since they all started at 0 and got changed precisely once,
// there will always be 3 changes
diff.Compress();
Assert.True(diff.IsCompressed);
Assert.Equal(3, diff.Changes.Count);
foreach (var change in diff.Changes)
{
Assert.True(currentValues.ContainsKey(change.Position));
Assert.Equal(0, change.OldValue);
Assert.Equal(currentValues[change.Position], change.NewValue);
}
}
