Added Pick functionality to builders

Author: mwhelan

TestStack.Dossier.Tests/Picking/PickingTests.cs

@@ -0,0 +1,48 @@
+using System.Linq;
+using Shouldly;
+using TestStack.Dossier.Lists;
+using TestStack.Dossier.Picking;
+using TestStack.Dossier.Tests.TestHelpers.Objects.Entities;
+using Xunit;
+
+namespace TestStack.Dossier.Tests.Picking
+{
+    public class PickingTests
+    {
+        [Fact]
+        public void RandomItemFrom_should_add_items_from_list_randomly()
+        {
+            var addresses = Builder<Address>.CreateListOfSize(15).BuildList();
+            var customers = Builder<Customer>
+                .CreateListOfSize(15)
+                .All()
+                .Set(x => x.PostalAddress, Pick.RandomItemFrom(addresses).Next)
+                .BuildList();
+
+            var uniqueAddresses = customers.Select(x => x.PostalAddress).Distinct().Count();
+            uniqueAddresses.ShouldBeGreaterThan(3);
+            uniqueAddresses.ShouldBeLessThan(15);
+        }
+
+        [Fact]
+        public void RepeatingSequenceFrom_should_add_items_from_list_sequentially_and_repeat_when_list_completes()
+        {
+            var addresses = Builder<Address>.CreateListOfSize(3).BuildList();
+            var customers = Builder<Customer>
+                .CreateListOfSize(9)
+                .All()
+                .Set(x => x.PostalAddress, Pick.RepeatingSequenceFrom(addresses).Next)
+                .BuildList();
+
+            for (int i = 0; i < 2; i++)
+            {
+                var address = customers[i].PostalAddress;
+                address.ShouldBeSameAs(customers[i + 3].PostalAddress);
+                address.ShouldBeSameAs(customers[i + 6].PostalAddress);
+
+                address.ShouldNotBeSameAs(customers[i + 1].PostalAddress);
+                address.ShouldNotBeSameAs(customers[i + 2].PostalAddress);
+            }
+        }
+    }
+}

TestStack.Dossier.Tests/TestStack.Dossier.Tests.csproj

@@ -58,6 +58,7 @@
     <Compile Include="Builder_CreateListTests.cs" />
     <Compile Include="Builder_CreateNewTests.cs" />
     <Compile Include="Builder_SetUsingBuilderTests.cs" />
+    <Compile Include="Picking\PickingTests.cs" />
     <Compile Include="TestHelpers\Builders\AddressViewModelBuilder.cs" />
     <Compile Include="TestHelpers\Builders\AutoConstructorCustomerBuilder.cs" />
     <Compile Include="ChildBuilderTests.cs" />
@@ -119,6 +120,7 @@
       <Name>TestStack.Dossier</Name>
     </ProjectReference>
   </ItemGroup>
+  <ItemGroup />
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.

TestStack.Dossier/Picking/ItemPicker.cs

@@ -0,0 +1,38 @@
+using System.Collections.Generic;
+using TestStack.Dossier.DataSources.Generators;
+
+namespace TestStack.Dossier.Picking
+{
+    /// <summary>
+    /// The base class with all of the item picking functionality
+    /// </summary>
+    /// <typeparam name="T"></typeparam>
+    public abstract class ItemPicker<T>
+    {
+        private readonly IList<T> _list;
+        private readonly IGenerator _generator;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ItemPicker{T}"/> class.
+        /// </summary>
+        /// <param name="list">The list.</param>
+        /// <param name="generator">The generator.</param>
+        protected ItemPicker(IList<T> list, IGenerator generator)
+        {
+            _list = list;
+            _generator = generator;
+            _generator.StartIndex = 0;
+            _generator.ListSize = _list.Count;
+        }
+
+        /// <summary>
+        /// Called to return the next item in the sequence.
+        /// </summary>
+        /// <returns></returns>
+        public T Next()
+        {
+            var index = _generator.Generate();
+            return _list[index];
+        }
+    }
+}

TestStack.Dossier/Picking/Pick.cs

@@ -0,0 +1,32 @@
+using System.Collections.Generic;
+
+namespace TestStack.Dossier.Picking
+{
+    /// <summary>
+    /// Pick a sequence of items from a collection of items according to different selection strategies.
+    /// </summary>
+    public class Pick
+    {
+        /// <summary>
+        /// Selects a random item from the list each time it is called.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="list">The list.</param>
+        /// <returns>The RandomItemPicker class.</returns>
+        public static RandomItemPicker<T> RandomItemFrom<T>(IList<T> list)
+        {
+            return new RandomItemPicker<T>(list);
+        }
+
+        /// <summary>
+        /// Selects each item sequentially from the list and starts again from the beginning when the list is exhausted.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="list">The list.</param>
+        /// <returns></returns>
+        public static RepeatingSequenceItemPicker<T> RepeatingSequenceFrom<T>(IList<T> list)
+        {
+            return new RepeatingSequenceItemPicker<T>(list);
+        }
+    }
+}

TestStack.Dossier/Picking/RandomItemPicker.cs

@@ -0,0 +1,20 @@
+using System.Collections.Generic;
+using TestStack.Dossier.DataSources.Generators;
+
+namespace TestStack.Dossier.Picking
+{
+    /// <summary>
+    /// Implements the random item strategy
+    /// </summary>
+    /// <typeparam name="T"></typeparam>
+    /// <seealso cref="ItemPicker{T}" />
+    public class RandomItemPicker<T> : ItemPicker<T>
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="RandomItemPicker{T}"/> class.
+        /// </summary>
+        /// <param name="list">The list.</param>
+        public RandomItemPicker(IList<T> list)
+            : base(list, new RandomGenerator()) { }
+    }
+}

TestStack.Dossier/Picking/RepeatingSequenceItemPicker.cs

@@ -0,0 +1,20 @@
+using System.Collections.Generic;
+using TestStack.Dossier.DataSources.Generators;
+
+namespace TestStack.Dossier.Picking
+{
+    /// <summary>
+    /// Implements the repeatable sequence strategy
+    /// </summary>
+    /// <typeparam name="T"></typeparam>
+    /// <seealso cref="ItemPicker{T}" />
+    public class RepeatingSequenceItemPicker<T> : ItemPicker<T>
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="RepeatingSequenceItemPicker{T}"/> class.
+        /// </summary>
+        /// <param name="list">The list.</param>
+        public RepeatingSequenceItemPicker(IList<T> list)
+            : base(list, new SequentialGenerator()) { }
+    }
+}

TestStack.Dossier/TestStack.Dossier.csproj

@@ -94,6 +94,10 @@
     <Compile Include="NullingExpandoObject.cs" />
     <Compile Include="Factories\IFactory.cs" />
     <Compile Include="PathExpressionVisitor.cs" />
+    <Compile Include="Picking\ItemPicker.cs" />
+    <Compile Include="Picking\Pick.cs" />
+    <Compile Include="Picking\RandomItemPicker.cs" />
+    <Compile Include="Picking\RepeatingSequenceItemPicker.cs" />
     <Compile Include="Reflector.cs" />
     <Compile Include="Suppliers\DefaultEmailValueSupplier.cs" />
     <Compile Include="Suppliers\DefaultLastNameValueSupplier.cs" />