title: tSQLt There was also a ROLLBACK ERROR in Private_RunTest
body: <p>Whenever I use ExpectException I receive the following error: (There was also a ROLLBACK ERROR --> The current transaction cannot be committed and cannot be rolled back to a savepoint. Roll back the entire transaction.{Private_RunTest,140})</p>
  
  <p>It appears that tSQLt is attempting a ROLLBACK after the fact that MSSQL has already performed the ROLLBACK due to the RAISERROR.
  I wrapped the following SELECT and SET statement in Private_RunTest with the following IF statement and it appeared to resolve the problem.</p>
  
  <pre><code>IF ISNULL(@ExpectException,0) &lt;&gt; 1 
    BEGIN
      SELECT @Msg = COALESCE(@Msg, '') + ' (There was also a ROLLBACK ERROR --&gt; ' + 
                    COALESCE(ERROR_MESSAGE(), '') + '{' + 
                    COALESCE(ERROR_PROCEDURE(), '') + ',' + 
                    COALESCE(CAST(ERROR_LINE() AS NVARCHAR), '') + '})';
      SET @Result = 'Error';
    END
  </code></pre>
  
  <p>Is this truly a bug and/or an appropriate fix?</p>