Added IsListBuilderProxy method to the builder base class

Author: robdmoore

NTestDataBuilder.Tests/BuildListTests.cs

@@ -11,6 +11,22 @@ namespace NTestDataBuilder.Tests
 {
     public class BuildListTests
     {
+        [Fact]
+        public void GivenANormalBuilderInstance_WhenCallingIsListBuilderProxy_ThenReturnFalse()
+        {
+            var builder = new BasicCustomerBuilder();
+
+            builder.IsListBuilderProxy().ShouldBe(false);
+        }
+
+        [Fact]
+        public void GivenAListBuilderProxyInstance_WhenCallingIsListBuilderProxy_ThenReturnTrue()
+        {
+            var builder = BasicCustomerBuilder.CreateListOfSize(1).TheFirst(1);
+
+            builder.IsListBuilderProxy().ShouldBe(true);
+        }
+
         [Fact]
         public void GivenListOfBuilders_WhenCallingBuildList_ThenAListOfEntitiesOfTheRightSizeShouldBeReturned()
         {

NTestDataBuilder/Lists/ListBuilderInterceptor.cs

@@ -16,6 +16,12 @@ public ListBuilderInterceptor(ListBuilder<TObject, TBuilder> builder)
 
         public void Intercept(IInvocation invocation)
         {
+            if (invocation.Method.Name == "IsListBuilderProxy")
+            {
+                invocation.Proceed();
+                return;
+            }
+
             if (invocation.Method.ReturnType != typeof (TBuilder))
             {
                 throw new InvalidOperationException("Non-fluent builder method invoked while creating a list of builders: " + invocation.Method.Name);

NTestDataBuilder/TestDataBuilder.cs

@@ -134,5 +134,14 @@ protected bool Has<TValue>(Expression<Func<TObject, TValue>> property)
         {
             return _properties.ContainsKey(PropertyNameGetter.Get(property));
         }
+
+        /// <summary>
+        /// Returns whether or not the builder instance is a proxy for building a list or an actual builder instance.
+        /// </summary>
+        /// <returns>Whether or not the instance is a list builder proxy</returns>
+        public virtual bool IsListBuilderProxy()
+        {
+            return ListBuilder != null;
+        }
     }
 }