New: Custom Format Spec Validation

Fixes #7405

src/NzbDrone.Core/CustomFormats/Specifications/QualityModifierSpecification.cs

@@ -1,11 +1,31 @@
+using System;
+using FluentValidation;
 using NzbDrone.Core.Annotations;
 using NzbDrone.Core.Parser.Model;
 using NzbDrone.Core.Qualities;
+using NzbDrone.Core.Validation;
 
 namespace NzbDrone.Core.CustomFormats
 {
+    public class QualityModifierSpecificationValidator : AbstractValidator<QualityModifierSpecification>
+    {
+        public QualityModifierSpecificationValidator()
+        {
+            RuleFor(c => c.Value).NotEmpty();
+            RuleFor(c => c.Value).Custom((qualityValue, context) =>
+            {
+                if (!Enum.IsDefined(typeof(Modifier), qualityValue))
+                {
+                    context.AddFailure(string.Format("Invalid quality modifier condition value: {0}", qualityValue));
+                }
+            });
+        }
+    }
+
     public class QualityModifierSpecification : CustomFormatSpecificationBase
     {
+        private static readonly QualityModifierSpecificationValidator Validator = new QualityModifierSpecificationValidator();
+
         public override int Order => 7;
         public override string ImplementationName => "Quality Modifier";
 
@@ -16,5 +36,10 @@ namespace NzbDrone.Core.CustomFormats
         {
             return (movieInfo?.Quality?.Quality?.Modifier ?? (int)Modifier.NONE) == (Modifier)Value;
         }
+
+        public override NzbDroneValidationResult Validate()
+        {
+            return new NzbDroneValidationResult(Validator.Validate(this));
+        }
     }
 }