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(); }