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DbContextOptions

As explained in ASP.NET Core in Action, 3e

DbContextOptions is the Entity Framework Core configuration object containing the settings and services used by a database context.

DbContextOptions is the configuration object that gives an EF Core DbContext its provider, connection, and related services. In tests, it can point the context at a SQLite database held in memory instead of a shared database. section 36.4

Configure a SQLite in-memory context in a few explicit steps:

  • Create a SqliteConnection with "DataSource=:memory:" and call Open(); the database lasts while this connection remains open. section 36.4
  • Create DbContextOptionsBuilder<AppDbContext>, call UseSqlite(connection), and retrieve the configured Options property. section 36.4
  • Pass the options to AppDbContext, call EnsureCreated(), add test data, and use separate context instances when testing reads and writes. section 36.4

SQLite-backed test context

var connection = new SqliteConnection("DataSource=:memory:"); connection.Open(); var options = new DbContextOptionsBuilder<AppDbContext>() .UseSqlite(connection) .Options; using var context = new AppDbContext(options); context.Database.EnsureCreated(); section 36.4

Listing 36.13 Using the in-memory database provider to test an EF Core DbContext
[Fact]
public void GetRecipeDetails_CanLoadFromContext()
{
    var connection = new SqliteConnection("DataSource=:memory:");   #1
    connection.Open();                                              #2
 
    var options = new DbContextOptionsBuilder<AppDbContext>()       #3
        .UseSqlite(connection)                                      #3
        .Options;                                                   #3
 
    using (var context = new AppDbContext(options))                 #4
    {
        context.Database.EnsureCreated();                           #5
        context.Recipes.AddRange(                                   #6
            new Recipe { RecipeId = 1, Name = "Recipe1" },          #6
            new Recipe { RecipeId = 2, Name = "Recipe2" },          #6
            new Recipe { RecipeId = 3, Name = "Recipe3" });         #6
        context.SaveChanges();                                      #7
    }
    using (var context = new AppDbContext(options))                 #8
    {
        var service = new RecipeService(context);                   #9
        var recipe = service.GetRecipe (id: 2);                     #10
        Assert.NotNull(recipe);                                     #11
        Assert.Equal(2, recipe.Id);                                 #11
        Assert.Equal("Recipe2", recipe.Name);                       #11
    }
}

Shows the complete test pattern, including connection setup, options creation, database preparation, seed data, and context usage. section 36.4

How ASP.NET Core in Action, 3e covers it

How deep it goes
Explains provider setup, connection lifetime, database creation, test data, and separate context usage.
Examples
Uses a SQLite in-memory connection, EnsureCreated, seeded recipes, and separate DbContext instances in a test.
What it assumes
Assumes a DbContext and basic EF Core testing knowledge while demonstrating the options-building sequence explicitly.
What you can do after
Configure and test an EF Core DbContext against a SQLite in-memory database.
How it connects
Connects DbContextOptions with DbContext, DbContextOptionsBuilder, SQLite, EF Core providers, and dependency injection.
Cover of ASP.NET Core in Action, 3e
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