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 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.");
}
}
