public async Task TestConcurrentAccountRequestsAsync()
{
var logger = new MockLogger();
var cosmosState = new MockCosmosState(logger);
var client = new MockImageGalleryClient(cosmosState, logger);
await client.InitializeCosmosDbAsync();
// Try create a new account, and wait for it to be created before proceeding with the test.
var account = new Account("0", "alice", "*****@*****.**");
var result = await client.CreateAccountAsync(account);
Assert.IsTrue(result);
var updatedAccount = new Account("0", "alice", "*****@*****.**");
// Try update the account and delete it concurrently, which can cause a data race and a bug.
var updateTask = client.UpdateAccountAsync(updatedAccount);
var deleteTask = client.DeleteAccountAsync(updatedAccount.Id);
// Wait for the two concurrent requests to complete.
await Task.WhenAll(updateTask, deleteTask);
// Bug: the update request can nondeterministically fail due to an unhandled exception (500 error code).
// See the `Update` handler in the account controller for more info.
_ = updateTask.Result;
var deleteAccountRes = deleteTask.Result;
// deleteAccountRes.EnsureSuccessStatusCode();
Assert.IsTrue(deleteAccountRes);
}
public async Task TestFirstScenario()
{
// Initialize the mock in-memory DB and account manager.
var cosmosState = new MockCosmosState();
var database = new MockCosmosDatabase(cosmosState);
var accountContainer = await database.CreateContainerAsync(Constants.AccountContainerName);
var petImagesClient = new TestPetImagesClient(accountContainer);
// Create an account request payload
var account = new Account()
{
Name = "MyAccount"
};
// Call CreateAccount twice without awaiting, which makes both methods run
// asynchronously with each other.
var task1 = petImagesClient.CreateAccountAsync(account);
var task2 = petImagesClient.CreateAccountAsync(account);
// Then wait both requests to complete.
await Task.WhenAll(task1, task2);
var statusCode1 = task1.Result.StatusCode;
var statusCode2 = task2.Result.StatusCode;
// Finally, assert that only one of the two requests succeeded and the other
// failed. Note that we do not know which one of the two succeeded as the
// requests ran concurrently (this is why we use an exclusive OR).
Assert.IsTrue(
(statusCode1 == HttpStatusCode.OK && statusCode2 == HttpStatusCode.Conflict) ||
(statusCode1 == HttpStatusCode.Conflict && statusCode2 == HttpStatusCode.OK));
}
public async Task TestThirdScenario()
{
var cosmosState = new MockCosmosState();
var database = new MockCosmosDatabase(cosmosState);
var accountContainer = (MockCosmosContainer)await database.CreateContainerAsync(Constants.AccountContainerName);
var imageContainer = (MockCosmosContainer)await database.CreateContainerAsync(Constants.ImageContainerName);
var blobContainer = new MockBlobContainerProvider();
var messagingClient = new MockMessagingClient(blobContainer);
var petImagesClient = new TestPetImagesClient(accountContainer, imageContainer, blobContainer, messagingClient);
string accountName = "MyAccount";
string imageName = "pet.jpg";
// Create an account request payload
var account = new Account()
{
Name = accountName
};
var accountResult = await petImagesClient.CreateAccountAsync(account);
Assert.IsTrue(accountResult.StatusCode == HttpStatusCode.OK);
var task1 = petImagesClient.CreateOrUpdateImageAsync(accountName, new Image()
{
Name = imageName, Content = GetDogImageBytes()
});
var task2 = petImagesClient.CreateOrUpdateImageAsync(accountName, new Image()
{
Name = imageName, Content = GetCatImageBytes()
});
await Task.WhenAll(task1, task2);
Assert.IsTrue(task1.Result.StatusCode == HttpStatusCode.OK);
Assert.IsTrue(task1.Result.StatusCode == HttpStatusCode.OK);
var imageResult = await petImagesClient.GetImageAsync(accountName, imageName);
Assert.IsTrue(imageResult.StatusCode == HttpStatusCode.OK);
byte[] image = imageResult.Resource;
byte[] thumbnail;
while (true)
{
var thumbnailResult = await petImagesClient.GetImageThumbnailAsync(accountName, imageName);
if (thumbnailResult.StatusCode == HttpStatusCode.OK)
{
thumbnail = thumbnailResult.Resource;
break;
}
}
Assert.IsTrue(
(IsDogImage(image) && IsDogThumbnail(thumbnail)) ||
(IsCatImage(image) && IsCatThumbnail(thumbnail)));
}
public async Task TestSecondScenario()
{
var cosmosState = new MockCosmosState();
var database = new MockCosmosDatabase(cosmosState);
var accountContainer = (MockCosmosContainer)await database.CreateContainerAsync(Constants.AccountContainerName);
var imageContainer = (MockCosmosContainer)await database.CreateContainerAsync(Constants.ImageContainerName);
var blobContainer = new MockBlobContainerProvider();
var messagingClient = new MockMessagingClient(blobContainer);
var petImagesClient = new TestPetImagesClient(accountContainer, imageContainer, blobContainer, messagingClient);
string accountName = "MyAccount";
string imageName = "pet.jpg";
// Create an account request payload
var account = new Account()
{
Name = accountName
};
var accountResult = await petImagesClient.CreateAccountAsync(account);
Assert.IsTrue(accountResult.StatusCode == HttpStatusCode.OK);
imageContainer.EnableRandomizedFaults();
var task1 = petImagesClient.CreateImageAsync(accountName, new Image()
{
Name = imageName, Content = GetDogImageBytes()
});
var task2 = petImagesClient.CreateImageAsync(accountName, new Image()
{
Name = imageName, Content = GetDogImageBytes()
});
await Task.WhenAll(task1, task2);
var statusCode1 = task1.Result.StatusCode;
var statusCode2 = task2.Result.StatusCode;
imageContainer.DisableRandomizedFaults();
Assert.IsTrue(statusCode1 == HttpStatusCode.OK || statusCode1 == HttpStatusCode.Conflict || statusCode1 == HttpStatusCode.ServiceUnavailable);
Assert.IsTrue(statusCode2 == HttpStatusCode.OK || statusCode2 == HttpStatusCode.Conflict || statusCode2 == HttpStatusCode.ServiceUnavailable);
if (task1.Result.StatusCode == HttpStatusCode.OK || task2.Result.StatusCode == HttpStatusCode.OK)
{
var imageContentResult = await petImagesClient.GetImageAsync(accountName, imageName);
Assert.IsTrue(imageContentResult.StatusCode == HttpStatusCode.OK);
Assert.IsTrue(IsDogImage(imageContentResult.Resource));
}
}
public async Task TestConcurrentAccountAndImageRequestsAsync()
{
var logger = new MockLogger();
var cosmosState = new MockCosmosState(logger);
var client = new MockImageGalleryClient(cosmosState, logger);
IDatabaseProvider databaseProvider = await client.InitializeCosmosDbAsync();
// Try create a new account, and wait for it to be created before proceeding with the test.
var account = new Account("0", "alice", "*****@*****.**");
await client.CreateAccountAsync(account);
// Try store the image and delete the account concurrently, which can cause a data race and a bug.
var image = new Image(account.Id, "beach", Encoding.Default.GetBytes("waves"));
var storeImageTask = client.CreateOrUpdateImageAsync(image);
var deleteAccountTask = client.DeleteAccountAsync(account.Id);
// Wait for the two concurrent requests to complete.
await Task.WhenAll(storeImageTask, deleteAccountTask);
// BUG: The above two concurrent requests can race and result into the image being stored
// in an "orphan" container in Azure Storage, even if the associated account was deleted.
// Check that the image was deleted from Azure Storage.
var exists = await client.AzureStorageProvider.ExistsBlobAsync(Constants.GetContainerName(account.Id), image.Name);
if (exists)
{
throw new AssertFailedException("The image was not deleted from Azure Blob Storage.");
}
// Check that the account was deleted from Cosmos DB.
var accountContainer = databaseProvider.GetContainer(Constants.AccountCollectionName);
exists = await accountContainer.ExistsItemAsync <AccountEntity>(account.Id, account.Id);
if (exists)
{
throw new AssertFailedException("The account was not deleted from Cosmos DB.");
}
}