@angular/core/testing has no exported member 'MockApplicationRef'
<p>I want to run my old angular2 unit-test with new RC4 version, but
I have a problem.</p>

<p>What happened to MockApplicationRef ?</p>

<p>What I should use here instead ?</p>

<pre><code>provide(ApplicationRef, { useClass: MockApplicationRef})
</code></pre>