EF Logging

ActualTest.cs

        public void TestIndex()
        {
            var memoryTarget = TestLoggingExtensions.SetupNLogMemoryTarget();

            var controller = new PollsController();
            controller.Index();

            Approvals.VerifyAll(memoryTarget.Logs.FilterOutMigrationLogs(), "log");
        }

CommandsOnlyFormatter.cs

public class CommandsOnlyFormatter : DatabaseLogFormatter
{
	public CommandsOnlyFormatter(DbContext context, Action<string> writeAction)
		: base(context, writeAction)
	{
	}

	public override void Opened(
		DbConnection connection, DbConnectionInterceptionContext interceptionContext)
	{
	}

	public override void LogCommand<TResult>(
		DbCommand command, DbCommandInterceptionContext<TResult> interceptionContext)
	{
		var dbParameters = command.Parameters.OfType<DbParameter>().ToArray();
		if (dbParameters.Any())
		{
			Write(string.Join(Environment.NewLine, dbParameters.Select(FormatParameter))
				+ Environment.NewLine
				+ command.CommandText);
		}
		else
		{
			Write(command.CommandText);
		}
	}

	private static string FormatParameter(DbParameter p)
	{
		var sqlParam = p as SqlParameter;
		var value = p.Value;
		if (p.Value == DBNull.Value || p.Value == null)
		{
			value = "null";
		}
		else if (p.DbType == DbType.String || p.DbType == DbType.StringFixedLength)
		{
			value = string.Format("'{0}'", value);
		}

		if (sqlParam == null)
		{
			return string.Format("-- {0}={1} ({2})", p.ParameterName, value, p.DbType);
		}

		return string.Format("declare @{0} {1} = {2};", p.ParameterName, sqlParam.SqlDbType, value);
	}

	public override void Closed(
		DbConnection connection, DbConnectionInterceptionContext interceptionContext)
	{
	}

	public override void LogResult<TResult>(
		DbCommand command, DbCommandInterceptionContext<TResult> interceptionContext)
	{
	}
}

CustomDbConfiguration.cs

    public class CustomDbConfiguration : DbConfiguration
    {
        public CustomDbConfiguration()
        {
            SetDatabaseLogFormatter((c, wa) => new CommandsOnlyFormatter(c, wa));
        }
    }

EfPollsRepository.cs

        static Logger logger = LogManager.GetLogger("PollsContext");
        private PollsContext pollsContext;

        public EfPollsRepository()
        {
            pollsContext = new PollsContext();
            pollsContext.Database.Log = s => logger.Debug(s);
        }

TestLoggingExtensions.cs

    public static class TestLoggingExtensions
    {
        public static IEnumerable<string> FilterOutMigrationLogs(this IEnumerable<string> logs)
        {
            return logs.Where(l => !l.Contains("__MigrationHistory") && !l.Contains("EdmMetadata"));
        }

        public static MemoryTarget SetupNLogMemoryTarget()
        {
            var config = new LoggingConfiguration();
            var memoryTarget = new MemoryTarget { Layout = "${message}" };
            config.AddTarget("memory", memoryTarget);
            var ruleDebug = new LoggingRule("*", LogLevel.Debug, memoryTarget);
            config.LoggingRules.Add(ruleDebug);
            LogManager.Configuration = config;
            return memoryTarget;
        }
    }