Added generic attribute mapper and tested partial update model

CoreHelpers.WindowsAzure.Storage.Table.Abstractions/IStorageContext.cs

@@ -21,6 +21,8 @@ public interface IStorageContext : IDisposable
 
         void AddAttributeMapper(Type type);
 
+        void AddAttributeMapper<T>(String optionalTablenameOverride = null) where T: class;
+
         void AddAttributeMapper(Type type, String optionalTablenameOverride);
 
         void AddEntityMapper(Type entityType, String partitionKeyFormat, String rowKeyFormat, String tableName);

CoreHelpers.WindowsAzure.Storage.Table.Tests/ITS22PartialUpates.cs

@@ -0,0 +1,67 @@
+using System;
+using CoreHelpers.WindowsAzure.Storage.Table.Backup;
+using CoreHelpers.WindowsAzure.Storage.Table.Tests.Contracts;
+using CoreHelpers.WindowsAzure.Storage.Table.Tests.Extensions;
+using CoreHelpers.WindowsAzure.Storage.Table.Tests.Models;
+
+namespace CoreHelpers.WindowsAzure.Storage.Table.Tests
+{
+    public class ITS22PartialUpates
+    {
+        private readonly IStorageContext _rootContext;
+
+        public ITS22PartialUpates(IStorageContext context)
+        {
+            _rootContext = context;
+        }
+
+        [Fact]
+        public async Task CreateAndVerifyBackup()
+        {
+            using (var scp = _rootContext.CreateChildContext())
+            {
+                // set the tablename context
+                scp.SetTableContext();
+
+                // configure the entity mapper
+                scp.AddAttributeMapper<PartialUpdateModel>();
+
+                // verify we don't have any value
+                Assert.Empty(await scp.EnableAutoCreateTable().Query<PartialUpdateModel>().InAllPartitions().Now());
+
+
+                // insert the value with just on optional integer
+                await scp.MergeOrInsertAsync<PartialUpdateModel>(new PartialUpdateModel() { CustomerId = "C01", MeterId = "M01", Value01 = 1 });
+
+                var result = (await scp.EnableAutoCreateTable().Query<PartialUpdateModel>().Now()).First();
+                Assert.True(result.Value01.HasValue);
+                Assert.Equal(result.Value01, 1);
+                Assert.False(result.Value02.HasValue);
+                Assert.False(result.Value03.HasValue);
+
+                // add the second update with just Value02 and ensure that Value01 stays untouched
+                await scp.MergeOrInsertAsync<PartialUpdateModel>(new PartialUpdateModel() { CustomerId = "C01", MeterId = "M01", Value02 = 2 });
+
+                result = (await scp.EnableAutoCreateTable().Query<PartialUpdateModel>().Now()).First();
+                Assert.True(result.Value01.HasValue);
+                Assert.Equal(result.Value01, 1);
+                Assert.True(result.Value02.HasValue);
+                Assert.Equal(result.Value02, 2);
+                Assert.False(result.Value03.HasValue);
+
+                // replace the model with Value 03
+                await scp.InsertOrReplaceAsync<PartialUpdateModel>(new PartialUpdateModel() { CustomerId = "C01", MeterId = "M01", Value03 = 3 });
+
+                result = (await scp.EnableAutoCreateTable().Query<PartialUpdateModel>().Now()).First();
+                Assert.False(result.Value01.HasValue);                
+                Assert.False(result.Value02.HasValue);                
+                Assert.True(result.Value03.HasValue);
+                Assert.Equal(result.Value03, 3);
+
+                // clean up
+                scp.DropTable<PartialUpdateModel>();
+            }
+        }
+    }
+}
+

CoreHelpers.WindowsAzure.Storage.Table.Tests/Models/PartialUpdateModel.cs

@@ -0,0 +1,21 @@
+using System;
+using CoreHelpers.WindowsAzure.Storage.Table.Attributes;
+
+namespace CoreHelpers.WindowsAzure.Storage.Table.Tests.Models
+{
+    [Storable(Tablename = "PartialUpdate")]
+    public class PartialUpdateModel
+    {
+
+        [PartitionKey]
+        public string CustomerId { get; set; } = String.Empty;
+
+        [RowKey]
+        public string MeterId { get; set; } = String.Empty;
+
+        public int? Value01 { get; set; }
+        public int? Value02 { get; set; }
+        public int? Value03 { get; set; }        
+    }
+}
+

CoreHelpers.WindowsAzure.Storage.Table/StorageContextAttributeMapping.cs

@@ -44,6 +44,11 @@ internal void AddAttributeMapper(Assembly assembly)
             }
         }
 
+        public void AddAttributeMapper<T>(String optionalTablenameOverride = null) where T : class
+        {
+            AddAttributeMapper(typeof(T), optionalTablenameOverride);
+        }
+
         public void AddAttributeMapper(Type type)
         {
             AddAttributeMapper(type, string.Empty);