public void TestGetSelector()
 {
     Assert.Equal("=", _whereAttributeManager.GetSelector(WhereType.Eq));
     Assert.Equal("<>", _whereAttributeManager.GetSelector(WhereType.NotEq));
     Assert.Equal(">", _whereAttributeManager.GetSelector(WhereType.Gt));
     Assert.Equal("<", _whereAttributeManager.GetSelector(WhereType.Lt));
     Assert.Equal(">=", _whereAttributeManager.GetSelector(WhereType.GtEq));
     Assert.Equal("<=", _whereAttributeManager.GetSelector(WhereType.LtEq));
     Assert.Equal("Like", _whereAttributeManager.GetSelector(WhereType.Like));
     Assert.Equal("is null", _whereAttributeManager.GetSelector(WhereType.IsNull));
     Assert.Equal("is not null", _whereAttributeManager.GetSelector(WhereType.IsNotNull));
     Assert.Equal("in", _whereAttributeManager.GetSelector(WhereType.In));
     Assert.Equal("not in", _whereAttributeManager.GetSelector(WhereType.NotIn));
 }