title: Expected invocation on the mock at least once, but was never performed
body: <p>First of all, I googled all SO posts on this but none helped me. I get the exception on the subject on below piece.</p>
  
  <pre><code> [Test]
      public void TestInv()
      {
          string inReference = "123";
          _Service.Setup(q=&gt; q.InvoiceS(inReference ));
          _Service.Verify(q =&gt; q.InvoiceS(inReference ), Times.AtLeastOnce());
      }
  </code></pre>