ASP.Net MVC: how to write unit test code when working with ValidationAttribute and IClientValidatable

问题

apologized to post bit similar question here. i am bit familiar with asp.net mvc but very new in unit testing. do not think that i know lot just see my reputation in stackoverflow.

i like to know how to write unit test code for IsValid and IEnumerable<ModelClientValidationRule> GetClientValidationRules

here i am pasting my code including my model. so anyone help me to write unit test code for the above two function. i am new in unit testing and working with VS2013 and using VS unit testing framework.

my main problem is how to write unit test code for this function specifically IEnumerable<ModelClientValidationRule> GetClientValidationRules

so here is my full code. anyone who often work with unit test then please see and come with code and suggestion if possible. thanks

Model

public class DateValTest
    {
        [Display(Name = "Start Date")]
        [DataType(DataType.Date), DisplayFormat(DataFormatString = "{0:MM/dd/yyyy}", ApplyFormatInEditMode = true)]
        public DateTime? StartDate { get; set; }

        [Display(Name = "End Date")]
        [DataType(DataType.Date), DisplayFormat(DataFormatString = "{0:MM/dd/yyyy}", ApplyFormatInEditMode = true)]
        [DateGreaterThanAttribute(otherPropertyName = "StartDate", ErrorMessage = "End date must be greater than start date")]
        public DateTime?  EndDate { get; set; }
    }

custom validation code

public class DateGreaterThanAttribute : ValidationAttribute, IClientValidatable
    {
        public string otherPropertyName;
        public DateGreaterThanAttribute() { }
        public DateGreaterThanAttribute(string otherPropertyName, string errorMessage)
            : base(errorMessage)
        {
            this.otherPropertyName = otherPropertyName;
        }

        protected override ValidationResult IsValid(object value, ValidationContext validationContext)
        {
            ValidationResult validationResult = ValidationResult.Success;
            try
            {
                // Using reflection we can get a reference to the other date property, in this example the project start date
                var containerType = validationContext.ObjectInstance.GetType();
                var field = containerType.GetProperty(this.otherPropertyName);
                var extensionValue = field.GetValue(validationContext.ObjectInstance, null);
                if(extensionValue==null)
                {
                    //validationResult = new ValidationResult("Start Date is empty");
                    return validationResult;
                }
                var datatype = extensionValue.GetType();

                //var otherPropertyInfo = validationContext.ObjectInstance.GetType().GetProperty(this.otherPropertyName);
                if (field == null)
                    return new ValidationResult(String.Format("Unknown property: {0}.", otherPropertyName));
                // Let's check that otherProperty is of type DateTime as we expect it to be
                if ((field.PropertyType == typeof(DateTime) || (field.PropertyType.IsGenericType && field.PropertyType == typeof(Nullable<DateTime>))))
                {
                    DateTime toValidate = (DateTime)value;
                    DateTime referenceProperty = (DateTime)field.GetValue(validationContext.ObjectInstance, null);
                    // if the end date is lower than the start date, than the validationResult will be set to false and return
                    // a properly formatted error message
                    if (toValidate.CompareTo(referenceProperty) < 1)
                    {
                        validationResult = new ValidationResult(ErrorMessageString);
                    }
                }
                else
                {
                    validationResult = new ValidationResult("An error occurred while validating the property. OtherProperty is not of type DateTime");
                }
            }
            catch (Exception ex)
            {
                // Do stuff, i.e. log the exception
                // Let it go through the upper levels, something bad happened
                throw ex;
            }

            return validationResult;
        }

        public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
        {
            var rule = new ModelClientValidationRule
            {
                ErrorMessage = FormatErrorMessage(metadata.GetDisplayName()),
                ValidationType = "isgreater",
            };
            rule.ValidationParameters.Add("otherproperty", otherPropertyName);
            yield return rule;
        }
    }

回答1:

What you want to do is test that if the value of EndDate is less than the value of StartDate, then the model is invalid, i.e. that the IsValid() method will throw a ValidationException

// Test that if the end date is less than the start date its invalid
[TestMethod]
[ExpectedException(typeof(ValidationException))]
public void TestEndDateIsInvalidIfLessThanStartDate()
{
    // Initialize a model with invalid values
    DateValTest model = new DateValTest(){ StartDate = DateTime.Today, EndDate = DateTime.Today.AddDays(-1) };
    ValidationContext context = new ValidationContext(model);
    DateGreaterThanAttribute attribute = new DateGreaterThanAttribute("StartDate");
    attribute.Validate(model.EndDate, context);   
}

When you run the test, if will succeed. Conversely if you were to initialize the model using

DateValTest model = new DateValTest(){ StartDate = DateTime.Today, EndDate = DateTime.Today.AddDays(1) };

the test would fail because the model is valid.

来源：https://stackoverflow.com/questions/36100027/asp-net-mvc-how-to-write-unit-test-code-when-working-with-validationattribute-a