This post assumes you have Visual Studio 2010 installed on your machine and have the NuGet extension installed. If the latter is not true, see the instructions and get that done<\/a>.<\/p>\n Also, you must have SQL Server Compact Edition 4.0<\/a> installed.<\/p>\n Given that, let\u2019s proceed.<\/p>\n Data Layer and NuGet<\/strong><\/p>\n The first step is to create a data layer project in your solution. This is just a simple class library like the ones found in other ESI projects.<\/p>\n Let\u2019s use NuGet to bring Microsoft Entity Framework (EF) 4.2 into the solution. Right-click on your data project\u2019s References node and pull up the NuGet Package Manager:<\/p>\n Find the Entity Framework project and install it.<\/p>\n Next, find and install the Beta version of Entity Framework Migrations:<\/p>\n The last NuGet package we want to install is SQL Server Compact Edition:<\/p>\n Core Shared Modules<\/strong><\/p>\n We\u2019re going to create a simple Employee table in the EF \u201cCode First\u201d style, so we will have neither a database project with a SQL table object or an EF object model with generated class definitions.<\/p>\n Instead, we\u2019re going to have a plain-old-CLR-object (POCO) class of our own to act as the model for the table. Since this class will be used to move data around layers of the solution, let\u2019s create another new class library to contain it. Let\u2019s call this the \u201ccore\u201d library.<\/p>\n Then add a class called EmployeeDTO to the core library:<\/p>\n (Yes, putting this class in a separate library is overkill for this example, but in a production-grade application, you\u2019ll want to have a core library for these and other classes. Think of extension methods, etc., as well.)<\/p>\n Data Layer Functionality<\/strong><\/p>\n With our POCO in place we can create our application\u2019s data context object:<\/p>\n (In the DataContext class, the OnModelCreating method is used to map the context\u2019s Employees property to the Employee table in our database.)<\/p>\n Next, we\u2019ll create an \u201cemployee migration\u201d class in our data project\u2019s Migrations folder (which was created by NuGet when we installed the Migrations package):<\/p>\n This class is used by EF Migrations to create the actual database table in the SQL CE database. In this simple example, pay particular attention to the Id column, which is declared as a SQL Identity. This will be used later in the testing process.<\/p>\n A Basic Test<\/strong><\/p>\n Let\u2019s create a 3rd project in our solution for testing purposes, then add a basic unit test class like this one:<\/p>\n The \u201cCan_insert\u201d test is perfectly clear, but where does the DataContext object come from? To instantiate our one-off SQL CE database instance, we need to create a custom database factory.<\/p>\n Creating a Database Instance<\/strong><\/p>\n In an EF application, the database context acts as a wrapper around a connection to the database. Before we can get a connection in our test library, we need to migrate our database schema to SQL CE. <\/p>\n Our test data context factory does that, then returns a data context to the test:<\/p>\n Dissecting the Test<\/strong><\/p>\n The unit test we wrote a moment ago is no different than any other. It arranges, acts, and asserts as usual. The only difference is that the test class\u2019 initialization method has created a scratch database for us to work with.<\/p>\n Conclusion<\/strong><\/p>\n When the test(s) are run, the database is created and made available to the test via the context object, then the data operation is invoked.<\/p>\n It\u2019s easy to imagine a more complex test doing additional arrangement to set up a particular testing scenario, then executing the required business rule code and evaluating the results.<\/p>\n It\u2019s also easy to imagine using the database generation to create development and test databases, particularly during the early phases of a project.<\/p>\n This project is in TFS under the $\/DeveloperTools\/ProofOfConcept\/DbUnitTesting folder.<\/p>\n Primary Reference<\/strong><\/p>\n http:\/\/iamnotmyself.com\/2011\/12\/18\/test-driven-evolutionary-design-with-entity-framework\/<\/a><\/p>\n https:\/\/github.com\/NotMyself\/SignMeUp<\/a><\/p>\n Other References<\/strong><\/p>\n http:\/\/docs.nuget.org\/docs\/start-here\/managing-nuget-packages-using-the-dialog<\/a><\/p>\n http:\/\/blogs.msdn.com\/b\/adonet\/archive\/2011\/11\/29\/code-first-migrations-beta-1-released.aspx<\/a><\/p>\n http:\/\/www.microsoft.com\/download\/en\/details.aspx?id=17876<\/a><\/p>\n![\"image\"](\"http:\/\/bcs.system.tamus.edu\/images\/MarcBlogs\/image_thumb6C769D89A26A.png\" "\\"image\\"")
<\/a><\/p>\n![\"SNAGHTMLe8df439\"](\"http:\/\/bcs.system.tamus.edu\/images\/MarcBlogs\/snaghtmle8df439_thumb-1-.png\" "\\"SNAGHTMLe8df439\\"")
<\/a><\/p>\n![\"SNAGHTMLe8fc406\"](\"http:\/\/bcs.system.tamus.edu\/images\/MarcBlogs\/snaghtmle8fc406_thumb-3-.png\" "\\"SNAGHTMLe8fc406\\"")
<\/a><\/p>\n![\"SNAGHTMLe9314a5\"](\"http:\/\/bcs.system.tamus.edu\/images\/MarcBlogs\/snaghtmle9314a5_thumb-2-.png\" "\\"SNAGHTMLe9314a5\\"")
<\/a><\/p>\n <\/pre>\n
![\"image\"](\"http:\/\/bcs.system.tamus.edu\/images\/MarcBlogs\/image_thumb-2-B464D733686E.png\" "\\"image\\"")
<\/a><\/pre>\n <\/pre>\n
<\/pre>\n
![\"image\"](\"http:\/\/bcs.system.tamus.edu\/images\/MarcBlogs\/image_thumb-9-05B370A5F03C.png\" "\\"image\\"")
<\/a><\/p>\n![\"image\"](\"http:\/\/bcs.system.tamus.edu\/images\/MarcBlogs\/image_thumb-18-4B0171353431.png\" "\\"image\\"")
<\/a><\/p>\n![\"image\"](\"http:\/\/bcs.system.tamus.edu\/images\/MarcBlogs\/image_thumb-19-7161190B78FB.png\" "\\"image\\"")
<\/a><\/p>\n![\"image\"](\"http:\/\/bcs.system.tamus.edu\/images\/MarcBlogs\/image_thumb-20-20984296161D.png\" "\\"image\\"")
<\/a><\/p>\n