public void Should_not_validate_when_input_is_null()
{
String value = null;
var validationRule = new RequiredValidationRule();
var result = validationRule.Validate(value, null);
Assert.IsFalse(result.IsValid);
Assert.IsNotNull(result.ErrorContent);
}
public void Should_validate_only_when_input_has_been_specified()
{
var value = "entered input";
var validationRule = new RequiredValidationRule();
var result = validationRule.Validate(value, null);
Assert.IsTrue(result.IsValid);
}