Unit testing QueryWithResultSetExtractor

[robsosno]

I've recently made unit tests for my dao classes. It is not quite obvious how to do that. So I would like to show my approach.
I'll show this on example taken from Spring.Net - DataQuickStart/GenericTemplate.
Method to be tested from ResultSetExtractorDao class:

        public virtual IList<string> GetCustomerNameByCountryAndCity(string country, string city)
        {
            IDbParametersBuilder builder = CreateDbParametersBuilder();
            builder.Create().Name("Country").Type(DbType.String).Size(15).Value(country);
            builder.Create().Name("City").Type(DbType.String).Size(15).Value(city);
            var parameters = builder.GetParameters();

            return AdoTemplate.QueryWithResultSetExtractorDelegate(CommandType.Text,
                                                customerByCountryAndCityCommandText,
                                                (IDataReader reader) =>
                                                {
                                                    IList<string> customerList = new List<string>();
                                                    while (reader.Read())
                                                    {
                                                        string contactName = reader.GetString(0);
                                                        customerList.Add(contactName);
                                                    }

                                                    return customerList;
                                                },
                                                parameters);
        }

Test with NUnit, FakeItEasy, FluentAssertions and .NET 6:

        private AdoTemplate adoTemplate;
        private ResultSetExtractorDao resultSetExtractorDao;

        [SetUp]
        public void Init()
        {
            adoTemplate = A.Fake<AdoTemplate>();
            resultSetExtractorDao = new ResultSetExtractorDao();
            FieldInfo adoTemplateField = typeof(AdoDaoSupport).GetField("adoTemplate", BindingFlags.NonPublic | BindingFlags.Instance);
            adoTemplateField.SetValue(resultSetExtractorDao, adoTemplate);
        }

        [Test]
        public void GetCustomerNameByCountryAndCityTest()
        {
            // Arrange
            IList<string> refreshStatusDtos = new List<string>();
            var fakeReader = A.Fake<IDataReader>();
            A.CallTo(() => fakeReader.Read()).Returns(true).Once().Then.Returns(false);
            A.CallTo(() => fakeReader.GetString(0)).Returns("Hanna Moos");

            A.CallTo(() => adoTemplate.QueryWithResultSetExtractorDelegate(
                System.Data.CommandType.Text,
                A<string>.Ignored,
                A<ResultSetExtractorDelegate<IList<string>>>.Ignored,
                A<IDbParameters>.Ignored))
            .ReturnsLazily(
                x =>
                {
                    var extractorDelegate = x.Arguments.Get<ResultSetExtractorDelegate<IList<string>>>(2);
                    return extractorDelegate(fakeReader);
                });

            // Act
            var result = resultSetExtractorDao.GetCustomerNameByCountryAndCity("Germany", "Mannheim");

            // Assert
            result.Count.Should().Be(1);
            var item = result[0];
            item.Should().Be("Hanna Moos");
        }

Some may wonder what's the purpose of this test. I work in a corporate where code is automatically scanned and it is required to get some minimum coverage to pass quality gate.
This test is not very useful. But it has one important advantage: it has 100% code coverage.
I see that nowadays even most respectable companies like Baeldung are using similar approach - see Unit Test With Mock Object