public async Task EnsuresNonNullArguments()
{
var client = new ObservableFollowersClient(Substitute.For<IGitHubClient>());
await Assert.ThrowsAsync<ArgumentNullException>(() => client.Follow(null).ToTask());
await Assert.ThrowsAsync<ArgumentException>(() => client.Follow("").ToTask());
}
public void FollowFromClientUserFollowers()
{
var githubClient = Substitute.For<IGitHubClient>();
var client = new ObservableFollowersClient(githubClient);
client.Follow("alfhenrik");
githubClient.User.Followers.Received()
.Follow("alfhenrik");
}