DbConnectionProviderTests.cs

[TestFixture]
public class when_getting_the_a_connection
{
    [Test]
    public void then_should_return_a_new_instance_of_an_odbc_connection()
    {
        // Arrange
        const string connectionString = "Server=Localhost;";
        var config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
        config.ConnectionStrings.ConnectionStrings.Remove("AS400ConnectionString");
        config.ConnectionStrings.ConnectionStrings.Add(new ConnectionStringSettings("AS400ConnectionString", connectionString));
        config.Save(ConfigurationSaveMode.Modified, true);
        ConfigurationManager.RefreshSection("connectionStrings");

        var provider = new DbConnectionProvider();

        // Act
        var connection = provider.As400Connection;

        // Assert
        Assert.That(connection, Is.Not.Null.And.Matches<OdbcConnection>(c => c.ConnectionString == connectionString));
    }
}