单元测试一个AngularJS指令，该指令监视具有隔离范围的属性

I have a directive that uses an isolate scope to pass in data to a directive that changes over time. It watches for changes on that value and does some computation on each change. When I try to unit test the directive, I can not get the watch to trigger (trimmed for brevity, but the basic concept is shown below):I have a directive that uses an isolate scope t