Created Unassigned: System.InvalidOperationException was unhandled by user code HResult=-2146233079 Message=Sequence contains no matching element [760]

Attempting to add test data like this using EF 6.1.3:

```
using System;
using System.Data.Entity.Migrations;
using Cssd.IT.PortalIntegration.POCO.SISMid.BO;

namespace Cssd.IT.PortalIntegration.DataAccessTest
{
public class SISMidDataAccessTestData
{
public static void AddTestData(ISISMidDbContext context)
{
context.LookupGrade.AddOrUpdate(new LookupGrade { GradeCode = -1, Grade = "PK4" });
context.LookupGrade.AddOrUpdate(new LookupGrade { GradeCode = 0, Grade = "00" });
context.LookupGrade.AddOrUpdate(new LookupGrade { GradeCode = 1, Grade = "01" });
context.LookupGrade.AddOrUpdate(new LookupGrade { GradeCode = 6, Grade = "06" });
context.LookupGrade.AddOrUpdate(new LookupGrade { GradeCode = 9, Grade = "09" });
context.LookupGrade.AddOrUpdate(new LookupGrade { GradeCode = 12, Grade = "12" });
}
}
}
```

Here is the LookupGrade class:

```
namespace Cssd.IT.PortalIntegration.POCO.SISMid.BO
{
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity.Spatial;
using Cssd.IT.PortalIntegration.POCO.School.BO;

public partial class LookupGrade : IImportBusinessKey
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.None)]
public int GradeCode { get; set; }

[Required]
[StringLength(3)]
public string Grade { get; set; }

[Column(TypeName = "smalldatetime")]
public DateTime? CC_SISMIDRefreshDate { get; set; }

public string ImportBusinessKey
{
get { return this.GradeCode.ToString(); }
}
}
}

```

This is my database table, where GradeCode is an integer non-identity primary key:

```
/****** Script for SelectTopNRows command from SSMS ******/
SELECT TOP 1000 [GradeCode]
,[Grade]
,[CC_SISMIDRefreshDate]
FROM [CC_SISMID].[dbo].[LookupGrade]
```

When the first AddOrUpdate executes, receiving this exception:

```
System.InvalidOperationException was unhandled by user code
HResult=-2146233079
Message=Sequence contains no matching element
Source=System.Core
StackTrace:
at System.Linq.Enumerable.Single[TSource](IEnumerable`1 source, Func`2 predicate)
at System.Data.Entity.Utilities.DbProviderManifestExtensions.GetStoreTypeFromName(DbProviderManifest providerManifest, String name)
at System.Data.Entity.ModelConfiguration.Configuration.Properties.Primitive.PrimitivePropertyConfiguration.ConfigureColumn(EdmProperty column, EntityType table, DbProviderManifest providerManifest)
at System.Data.Entity.ModelConfiguration.Configuration.Properties.Primitive.PrimitivePropertyConfiguration.Configure(EdmProperty column, EntityType table, DbProviderManifest providerManifest, Boolean allowOverride, Boolean fillFromExistingConfiguration)
at System.Data.Entity.ModelConfiguration.Configuration.Properties.Primitive.PrimitivePropertyConfiguration.<>c__DisplayClass4.<Configure>b__3(Tuple`2 pm)
at System.Data.Entity.Utilities.IEnumerableExtensions.Each[T](IEnumerable`1 ts, Action`1 action)
at System.Data.Entity.ModelConfiguration.Configuration.Properties.Primitive.PrimitivePropertyConfiguration.Configure(IEnumerable`1 propertyMappings, DbProviderManifest providerManifest, Boolean allowOverride, Boolean fillFromExistingConfiguration)
at System.Data.Entity.ModelConfiguration.Configuration.Types.StructuralTypeConfiguration.ConfigurePropertyMappings(IList`1 propertyMappings, DbProviderManifest providerManifest, Boolean allowOverride)
at System.Data.Entity.ModelConfiguration.Configuration.Types.EntityTypeConfiguration.ConfigurePropertyMappings(DbDatabaseMapping databaseMapping, EntityType entityType, DbProviderManifest providerManifest, Boolean allowOverride)
at System.Data.Entity.ModelConfiguration.Configuration.Types.EntityTypeConfiguration.Configure(EntityType entityType, DbDatabaseMapping databaseMapping, DbProviderManifest providerManifest)
at System.Data.Entity.ModelConfiguration.Configuration.ModelConfiguration.ConfigureEntityTypes(DbDatabaseMapping databaseMapping, ICollection`1 entitySets, DbProviderManifest providerManifest)
at System.Data.Entity.ModelConfiguration.Configuration.ModelConfiguration.Configure(DbDatabaseMapping databaseMapping, DbProviderManifest providerManifest)
at System.Data.Entity.DbModelBuilder.Build(DbProviderManifest providerManifest, DbProviderInfo providerInfo)
at System.Data.Entity.DbModelBuilder.Build(DbConnection providerConnection)
at System.Data.Entity.Internal.LazyInternalContext.CreateModel(LazyInternalContext internalContext)
at System.Data.Entity.Internal.RetryLazy`2.GetValue(TInput input)
at System.Data.Entity.Internal.LazyInternalContext.InitializeContext()
at System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType)
at System.Data.Entity.Internal.Linq.InternalSet`1.Initialize()
at System.Data.Entity.Internal.Linq.InternalSet`1.get_InternalContext()
at System.Data.Entity.Migrations.DbSetMigrationsExtensions.GetKeyProperties[TEntity](Type entityType, InternalSet`1 internalSet)
at System.Data.Entity.Migrations.DbSetMigrationsExtensions.AddOrUpdate[TEntity](IDbSet`1 set, TEntity[] entities)
at Cssd.IT.PortalIntegration.DataAccessTest.SISMidDataAccessTestData.AddTestData(ISISMidDbContext context) in c:\DevProjects\IT_Portal\Source\PortalIntegration\Cssd.IT.PortalIntegration.DataAccessTest\SISMidDataAccessTestData.cs:line 12
at Cssd.IT.PortalIntegration.DataAccessTest.SISMidDataAccessTest.Setup() in c:\DevProjects\IT_Portal\Source\PortalIntegration\Cssd.IT.PortalIntegration.DataAccessTest\SISMidDataAccessTest.cs:line 27
InnerException:
```

Does anyone have any suggestions? The above error occurs only when attempting to test with Effort. When the unit test is run against SQL Server, it works fine. TIA.