nUnit-style [TestCase]

```
[TestCase("", 0)]
[TestCase("a", 1)]
[TestCase("zzz", 3)]
void GetLength_ReturnsLength(string name, int expectedLength) {
    var name = new NameBox(name);
    Assert.IsEqual(name.GetLength(), expectedLength);
}
```

Runs function multiple time with various parameters. 
