uid: in-memory-testing

title: In-Memory Testing

When performing integration testing, it's sometimes helpful to be able to use an in-memory database (such as Sqlite) to act as the database while tests are running. As a result, this article describes how you can accomplish this with FluentMigrator.

_Credit to Craig on this [StackOverflow answer](https://stackoverflow.com/a/66926940) that in turn created an issue for us to add this to the documentation._

_Note: Sqlite only keeps the in-memory database in memory for the time the process is running. In addition, all connection strings that utilize the same name will access the same database._

Create InMemory database, setup FluentMigrator and execute migrations during test setup:

public static IDisposable CreateInMemoryDatabase(Assembly AssemblyWithMigrations, IServiceCollection services = null)

{

if (services == null)

services = new ServiceCollection();

var connectionString = GetSharedConnectionString();

var connection = GetPersistantConnection(connectionString);

MigrateDb(services, connectionString, AssemblyWithMigrations);

services.AddSingleton<IConnectionFactory>(new InMemoryConnectionFactory(connectionString));

return services.BuildServiceProvider()

.GetRequiredService<IDisposableUnderlyingQueryingTool>();

}

private static string GetSharedConnectionString()

{

var dbName = Guid.NewGuid().ToString();

return $"Data Source={dbName};Mode=Memory;Cache=Shared";

}

private static void MigrateDb(IServiceCollection services, string connectionString, Assembly assemblyWithMigrations)

{

var sp = services.AddFluentMigratorCore()

.ConfigureRunner(fluentMigratorBuilder => fluentMigratorBuilder

.AddSQLite()

.WithGlobalConnectionString(connectionString)

.ScanIn(assemblyWithMigrations).For.Migrations()

)

.BuildServiceProvider();

var runner = sp.GetRequiredService<IMigrationRunner>();

runner.MigrateUp();

}

private static IDbConnection GetPersistantConnection(string connectionString)

{

var connection = new SqliteConnection(connectionString);

connection.Open();

return connection;

}

This serves as an example test utilizing the static methods above:

[TestFixture]

public Test : IDisposable {

private readonly IDisposable _holdingConnection;

[Test]

public Test() {

_holdingConnection = CreateInMemoryDatabase(typeof(MyFirstMigration).Assembly);

}

public void Dispose() {

_holdingConnection.Dispose();

}

}

| Package | Description |

| ------------------------- | ---------------------------------------------------------------------------------------------- |

| FluentMigrator | The base assembly needed to create migrations |

| FluentMigrator.Runner | The runner classes required for in-process execution of migrations |

| FluentMigrator.Console | The .NET 4.0/4.5/.NET Core 2.0 executable for out-of-process execution of migrations |

| FluentMigrator.MSBuild | The .NET 4.0/4.5/.NET Standard 2.0 task for MSBuild |

| FluentMigrator.DotNet.Cli | The .NET Core 2.1 executable that integrates into the .NET Core CLI tooling (`dotnet` command) |

- Check out the tour of FluentMigrator in our [Quickstart](xref:quickstart.md)

- We also started a [FAQ](xref:faq)

- How to create a [migration](xref:migration-example.md)

- Learn about the [fluent interface](fluent-interface.md)

- [Profiles](profiles.md) can be used to seed test data

- And then choose one of the [migration runners](migration-runners.md) to run your migrations

- [Database functions as default value](xref:db-functions)

- [Microsoft SQL Server specific extensions](xref:sql-server-extensions.md)

- [Using raw SQL](xref:raw-sql)

- [Auto-reversing migrations](xref:migration-auto-reversing)

- [Transaction modes for the migration runner](xref:migration-transaction-behavior)

- [In-Memory Testing](xref:in-memory-testing)

- [Dealing with multiple database types](multi-db-support.md)

- [Filter migrations run based on Tags](xref:migration-filter-tags)

- [Enforcing migration version numbering rules](xref:migration-attribute-custom)

- [Create custom metadata for the VersionInfo table](xref:version-table-metadata)

- [Release Notes](https://github.com/fluentmigrator/fluentmigrator/releases)

- [3.1 to 3.2](xref:upgrade-guide-3.1-to-3.2)

- [3.0 to 3.1](xref:upgrade-guide-3.0-to-3.1)

- [2.x to 3.0](xref:upgrade-guide-2.0-to-3.0)

- [Console](xref:runner-console)

- [dotnet-fm](xref:dotnet-fm)