public async Task GivenTheCurrentMigrations_WhenRunningThemInBothDirections_DatabaseIsCorrectlyMigrated()
{
// Arrange
string databaseName =
$"it--{nameof(GivenTheCurrentMigrations_WhenRunningThemInBothDirections_DatabaseIsCorrectlyMigrated)}";
DbContextOptions <TodoDbContext> dbContextOptions = GetDbContextOptions(databaseName);
await using TodoDbContext todoDbContext = new TodoDbContext(dbContextOptions);
bool isMigrationSuccessful;
try
{
await todoDbContext.Database.EnsureDeletedAsync();
IMigrator databaseMigrator = todoDbContext.GetInfrastructure().GetRequiredService <IMigrator>();
// Act
await databaseMigrator.MigrateAsync();
// Revert migrations by using a special migration identifier.
// See more here: https://docs.microsoft.com/en-us/ef/core/miscellaneous/cli/dotnet#dotnet-ef-database-update.
await databaseMigrator.MigrateAsync(BeforeFirstDatabaseMigration);
await databaseMigrator.MigrateAsync();
isMigrationSuccessful = true;
}
catch
{
isMigrationSuccessful = false;
}
finally
{
await todoDbContext.Database.EnsureDeletedAsync();
}
// Assert
isMigrationSuccessful.Should().BeTrue("migrations should work in both directions, up and down");
}
public async Task SaveChanges_WhenModifyingSameEntityUsingTwoConcurrentTransactions_ThrowsException()
{
// Arrange
string databaseName =
$"it--{nameof(SaveChanges_WhenModifyingSameEntityUsingTwoConcurrentTransactions_ThrowsException)}";
DbContextOptions <TodoDbContext> dbContextOptions = GetDbContextOptions(databaseName);
await using TodoDbContext firstTodoDbContext = new TodoDbContext(dbContextOptions);
IMigrator databaseMigrator = firstTodoDbContext.GetInfrastructure().GetRequiredService <IMigrator>();
await databaseMigrator.MigrateAsync();
try
{
string name = "ConcurrentlyAccessedTodoItem";
TodoItem todoItem = new TodoItem(name, "it")
{
IsComplete = false,
};
await firstTodoDbContext.TodoItems.AddAsync(todoItem);
await firstTodoDbContext.SaveChangesAsync();
await using IDbContextTransaction firstTransaction =
await firstTodoDbContext.Database.BeginTransactionAsync();
TodoItem todoItemFromFirstTransaction =
await firstTodoDbContext.TodoItems.FirstAsync(x => x.Name == name);
todoItemFromFirstTransaction.IsComplete = true;
todoItemFromFirstTransaction.LastUpdatedBy = Guid.NewGuid().ToString("N");
todoItemFromFirstTransaction.LastUpdatedOn = DateTime.UtcNow;
await using TodoDbContext secondTodoDbContext = new TodoDbContext(dbContextOptions);
await using IDbContextTransaction secondTransaction =
await secondTodoDbContext.Database.BeginTransactionAsync();
TodoItem todoItemFromSecondTransaction =
await secondTodoDbContext.TodoItems.FirstAsync(x => x.Name == name);
todoItemFromSecondTransaction.IsComplete = false;
todoItemFromSecondTransaction.LastUpdatedBy = Guid.NewGuid().ToString("N");
todoItemFromSecondTransaction.LastUpdatedOn = DateTime.UtcNow;
await firstTodoDbContext.SaveChangesAsync();
await firstTransaction.CommitAsync();
// Act
Func <Task> saveChangesAsyncCall = async() =>
{
// ReSharper disable AccessToDisposedClosure
await secondTodoDbContext.SaveChangesAsync();
await secondTransaction.CommitAsync();
// ReSharper restore AccessToDisposedClosure
};
// Assert
saveChangesAsyncCall.Should()
.ThrowExactly <DbUpdateConcurrencyException>(
"2 transactions were concurrently modifying the same entity");
}
finally
{
await firstTodoDbContext.Database.EnsureDeletedAsync();
}
}
