public void Break_BreaksIntoTwo(string whole, int splitIndex, string left, string right)
{
var it = DoAll(new Func <UndoableAction>[]
{
FromCommand <InsertTextCommand, string>(() => BlockAt(0).EndCursor().ToHandle(), whole),
FromCommand <BreakTextBlockCommand>(() => BlockAt(0).BeginCursor(splitIndex).ToHandle()),
});
DidYouKnow.That(Document.Root.ChildCount).Should().Be(2);
DidYouKnow.That(BlockAt(0)).Should().BeAssignableTo <TextBlock>();
DidYouKnow.That(BlockAt(1)).Should().BeAssignableTo <TextBlock>();
DidYouKnow.That(BlockAt(0).As <TextBlock>().AsText()).Should().Be(left);
DidYouKnow.That(BlockAt(1).As <TextBlock>().AsText()).Should().Be(right);
it.VerifyUndo();
}