I'm having a bit of trouble getting my head around testing my custom validation attribute. As the method signature is protected
when I invoke the IsValid
method in my unit test, I can't pass in a Mock<ValidationContext>
object, it's calling the base virtual bool IsValid(object value)
instead.
ValidationAttribute
protected override ValidationResult IsValid(object value, ValidationContext validationContext)
{
var otherPropertyInfo = validationContext.ObjectType.GetProperty(this.otherPropertyName);
var otherPropertyValue = otherPropertyInfo.GetValue(validationContext.ObjectInstance, null);
if (value != null)
{
if (otherPropertyValue == null)
{
return new ValidationResult(FormatErrorMessage(this.ErrorMessage));
}
}
return ValidationResult.Success;
}
Test
[Test]
public void Should_BeValid_WhenPropertyIsNullAndOtherPropertyIsNull()
{
var attribute = new OptionalIfAttribute("test");
var result = attribute.IsValid(null);
Assert.That(result, Is.True);
}
If I'm unable to pass in a mocked validation context, then how can I test this class properly?
You can use the Validator
class to perform the validation manually without having to mock anything. There is a brief article on it here. I would probably do something like
[Test]
public void Should_BeValid_WhenPropertyIsNullAndOtherPropertyIsNull()
{
var target = new ValidationTarget();
var context = new ValidationContext(target);
var results = new List<ValidationResult>();
var isValid = Validator.TryValidateObject(target, context, results, true);
Assert.That(isValid, Is.True);
}
private class ValidationTarget
{
public string X { get; set; }
[OptionalIf(nameof(X))]
public string OptionalIfX { get; set; }
}
You could optionally make assertions on results
.