public void TestPlacement()
{
Assert.Throws <ArgumentException>(() => Placement.Builder().Build());
Placement p = Placement.Builder().WithCluster("cluster").Build();
Assert.Equal("cluster", p.Cluster);
Assert.Null(p.Tags);
List <string> tags = new List <string> {
"a", "b"
};
p = Placement.Builder().WithCluster("cluster").WithTags(tags).Build();
Assert.Equal("cluster", p.Cluster);
Assert.Equal(2, p.Tags.Count);
}