public void GetValidationError_All_Item_2() { // Arrange var propertyName1 = "Item1"; var errorMessage1_1 = "ErrorMessage1_1."; var errorMessage1_2 = "ErrorMessage1_2."; var propertyName2 = "Item2"; var errorMessage2_1 = "ErrorMessage2_1."; var errorMessage2_2 = "ErrorMessage2_2."; var inner = new Dictionary <string, List <string> > { { propertyName1, new List <string> { errorMessage1_1, errorMessage1_2 } }, { propertyName2, new List <string> { errorMessage2_1, errorMessage2_2 } }, }; var dictionary = new ValidationDictionary(inner); // Act var actual = dictionary.GetValidationError(null); // Assert var expected = new List <string> { errorMessage1_1, errorMessage1_2, errorMessage2_1, errorMessage2_2, }; Assert.True(TestHelper.IsSameCollection(expected, actual)); }