public class MyExplicitlyTypedTests
    {
        [TestCaseSource(nameof(ExplicitTypeArgsTestCases))]
        public void ExplicitTypeArgs<T>(T input)
        {
            Assert.That(typeof(T), Is.EqualTo(typeof(long)));
        }

        private static IEnumerable<TestCaseData> ExplicitTypeArgsTestCases()
        {
            yield return new TestCaseData(2) { TypeArgs = new[] { typeof(long) } };
            yield return new TestCaseData(2L) { TypeArgs = new[] { typeof(long) } };
        }
    }