title: ApprovalTests with TestCase (Nunit) use the same approval file
body: <p>I have a problem that using ApprovalTests.Net and NUnit all the tests that are run use the same approval file which name originates from Test method name. </p>
  
  <p>Is it possible to specify somehow for each test case separate approval file? </p>
  
  <pre><code>[Test]
  [TestCase("test",TestName="Test1")]
  [TestCase("test2",TestName="Test2")]
  Testing_Method(string param)
  {
     //somestuff
     ObjectApprover.VerifyJson(someObject); // fails for second case 
                                            // because it uses the same 
                                            // approval file as the first case,
                                            // which is not the same
  }
  </code></pre>