public void AsInt_returns_integer_in_string(int value)
        {
            var testString = $"{value}";

            var result = HelperExtensions.AsInt(testString);

            Assert.That(result, Is.EqualTo(value));
        }
 public void AsInt_throws_if_invalid_string(string testString)
 {
     Assert.Throws <FormatException>(() => HelperExtensions.AsInt(testString));
 }