Add ignored file

Author: cdavernas

src/ServerlessWorkflow.Sdk/Services/Validation/SubflowReferenceValidator.cs

@@ -0,0 +1,32 @@
+using FluentValidation;
+using ServerlessWorkflow.Sdk.Models;
+
+namespace ServerlessWorkflow.Sdk.Services.Validation
+{
+    /// <summary>
+    /// Represents the service used to validate <see cref="SubflowReference"/>s
+    /// </summary>
+    public class SubflowReferenceValidator
+        : AbstractValidator<SubflowReference>
+    {
+
+        /// <summary>
+        /// Initializes a new <see cref="SubflowReferenceValidator"/>
+        /// </summary>
+        /// <param name="workflow">The <see cref="WorkflowDefinition"/> the <see cref="SubflowReference"/>s to validate belong to</param>
+        public SubflowReferenceValidator(WorkflowDefinition workflow)
+        {
+            this.Workflow = workflow;
+            this.RuleFor(w => w.WorkflowId)
+                .NotEmpty()
+                .WithErrorCode($"{nameof(SubflowReference)}.{nameof(SubflowReference.WorkflowId)}");
+        }
+
+        /// <summary>
+        /// Gets the <see cref="WorkflowDefinition"/> the <see cref="FunctionReference"/>s to validate belong to
+        /// </summary>
+        protected WorkflowDefinition Workflow { get; }
+
+    }
+
+}