Npgsql.Tests.CommandBuilderTests.DeriveParametersVarious C# (CSharp) Method

        public void DeriveParametersVarious()
        {
            using (var conn = OpenConnection())
            {
                // This function returns record because of the two Out (InOut & Out) parameters
                conn.ExecuteNonQuery(@"
                    CREATE OR REPLACE FUNCTION pg_temp.func(IN param1 INT, OUT param2 text, INOUT param3 INT) RETURNS record AS
                    '
                    BEGIN
                            param2 = ''sometext'';
                            param3 = param1 + param3;
                    END;
                    ' LANGUAGE 'plpgsql';
                ");

                var cmd = new NpgsqlCommand("pg_temp.func", conn) { CommandType = CommandType.StoredProcedure };
                NpgsqlCommandBuilder.DeriveParameters(cmd);
                Assert.That(cmd.Parameters, Has.Count.EqualTo(3));
                Assert.That(cmd.Parameters[0].Direction, Is.EqualTo(ParameterDirection.Input));
                Assert.That(cmd.Parameters[1].Direction, Is.EqualTo(ParameterDirection.Output));
                Assert.That(cmd.Parameters[2].Direction, Is.EqualTo(ParameterDirection.InputOutput));
                cmd.Parameters[0].Value = 5;
                cmd.Parameters[2].Value = 4;
                cmd.ExecuteNonQuery();
                Assert.That(cmd.Parameters[0].Value, Is.EqualTo(5));
                Assert.That(cmd.Parameters[1].Value, Is.EqualTo("sometext"));
                Assert.That(cmd.Parameters[2].Value, Is.EqualTo(9));
            }
        }