public void Zip()
{
Nullable <int> n = 2;
Nullable <int> n0 = null;
Assert.Throws <ArgumentNullException>(() => NullableExtensions.Zip <int, int, int>(n, n, null));
Func <int, int, int> selector = (a, b) => a + b;
Func <int, int, int> fail = (a, b) => throw new InvalidOperationException("Should not be called");
Assert.True(n.Zip(n, selector).HasValue);
Assert.False(n0.Zip(n, selector).HasValue);
Assert.False(n.Zip(n0, selector).HasValue);
Assert.False(n0.Zip(n0, selector).HasValue);
Assert.Equal(4, n.Zip(n, selector).Value);
Assert.False(n0.Zip(n, fail).HasValue);
Assert.False(n.Zip(n0, fail).HasValue);
Assert.False(n0.Zip(n0, fail).HasValue);
Assert.Equal((2, 2), n.Zip(n).Value);
}
