public async Task Construction_without_parameter_is_allowed_and_returns_null()
{
var provider = new ChainedAvatarProvider();
var image = await provider.GetAvatarAsync(_email1, _name1, _size);
Assert.Null(image);
}
public async Task Return_first_non_null_result()
{
var provider1 = Substitute.For <IAvatarProvider>();
var provider2 = Substitute.For <IAvatarProvider>();
var provider3 = Substitute.For <IAvatarProvider>();
// Register different images (for the same parameters)
// for each provider. This allows us to detect incorrect results.
// Case 1: First provider hit
provider1.GetAvatarAsync(_email1, _name1, _size).Returns(_img1);
provider2.GetAvatarAsync(_email1, _name1, _size).Returns(_img2);
provider3.GetAvatarAsync(_email1, _name1, _size).Returns(_img3);
// Case 2: Second provider hit
provider1.GetAvatarAsync(_email2, _name2, _size).Returns((Image)null);
provider2.GetAvatarAsync(_email2, _name2, _size).Returns(_img4);
provider3.GetAvatarAsync(_email2, _name2, _size).Returns(_img5);
// Case 3: Third provider hit
provider1.GetAvatarAsync(_email3, _name3, _size).Returns((Image)null);
provider2.GetAvatarAsync(_email3, _name3, _size).Returns((Image)null);
provider3.GetAvatarAsync(_email3, _name3, _size).Returns(_img6);
// Case 4: No provider hit
provider1.GetAvatarAsync(_email4, _name4, _size).Returns((Image)null);
provider2.GetAvatarAsync(_email4, _name4, _size).Returns((Image)null);
provider3.GetAvatarAsync(_email4, _name4, _size).Returns((Image)null);
var chainedProvider = new ChainedAvatarProvider(provider1, provider2, provider3);
var res1 = await chainedProvider.GetAvatarAsync(_email1, _name1, _size);
var res2 = await chainedProvider.GetAvatarAsync(_email2, _name2, _size);
var res3 = await chainedProvider.GetAvatarAsync(_email3, _name3, _size);
var res4 = await chainedProvider.GetAvatarAsync(_email4, _name4, _size);
Assert.AreSame(_img1, res1);
Assert.AreSame(_img4, res2);
Assert.AreSame(_img6, res3);
Assert.AreSame(null, res4);
}
