public void Where() { Nullable <int> n = 2; Nullable <int> n0 = null; Assert.Throws <ArgumentNullException>(() => NullableExtensions.Where <int>(n, null)); Assert.True(n.Where(i => i == 2).HasValue); Assert.False(n.Where(i => i == 3).HasValue); Assert.False(n0.Where(i => i == 2).HasValue); Assert.False(n0.Where(i => i == 3).HasValue); }