public void ToStringTest()
{
var actual = new FieldsContainer();
for (int i = 0; i < 9; i++)
{
actual.Fields.Add(new Field());
}
var expected = "|1|0|3|0|0|0|0|0|9|";
actual.InsertValue(0, 1);
actual.InsertValue(2, 3);
actual.InsertValue(8, 9);
Assert.AreEqual(expected, actual.ToString());
}