public async Task RequestsCorrectUrl()
{
var connection = Substitute.For <IApiConnection>();
var client = new ProductsClient(connection);
await client.GetDealsForProduct(123);
Received.InOrder(async() =>
{
await connection.Get <IReadOnlyList <Deal> >(Arg.Is <Uri>(u => u.ToString() == "products/123/deals"));
});
}