public void Map()
{
Nullable <int> n = 2;
Nullable <int> n0 = null;
Assert.Throws <ArgumentNullException>(() => NullableExtensions.Map <int, int>(n, null));
Func <int, int> selector = i => i * 2;
Assert.True(n.Map(selector).HasValue);
Assert.Equal(4, n.Map(selector).Value);
Assert.False(n0.Map(selector).HasValue);
// selector not called
Assert.False(n0.Map(new Func <int, int>(_ => throw new InvalidOperationException("Should not be called"))).HasValue);
}
