EfCore.InMemory.Transactions 1.0.0

EfCore.InMemory.Transactions

Seamless transaction support for EF Core InMemory provider. Eliminates "transactions with isolation level are not supported" errors in tests without changing production code.

The Problem

EF Core's InMemory provider throws exceptions when using transactions with isolation levels:

// This FAILS with InMemory provider:
await using var transaction = await _context.Database
    .BeginTransactionAsync(IsolationLevel.Serializable, ct);
// Exception: "Transactions with isolation level Serializable are not supported"

This forces you to either:

• ❌ Switch to SQLite in-memory (different provider, different behavior)
• ❌ Add if (IsInMemory) checks throughout your production code
• ❌ Restructure your code to not use transactions in tests

The Solution

This package provides two approaches:

Approach 1: Safe Extension Methods (Recommended for Direct DbContext Usage)

// Instead of:
await context.Database.BeginTransactionAsync(IsolationLevel.Serializable, ct);

// Use:
await context.Database.BeginTransactionSafeAsync(IsolationLevel.Serializable, ct);
// ✅ Works with both real database and InMemory!

Approach 2: UnitOfWork Pattern (Recommended for Clean Architecture)

If you use the UnitOfWork pattern, integrate InMemory detection in your UnitOfWork class:

public class UnitOfWork : IUnitOfWork
{
    private readonly AppDbContext _context;
    private readonly bool _isInMemoryDatabase;

    public UnitOfWork(AppDbContext context)
    {
        _context = context;
        _isInMemoryDatabase = _context.Database.IsInMemoryDatabase(); // Extension method
    }

    public Task<IDbContextTransaction> BeginTransactionAsync(
        IsolationLevel isolationLevel,
        CancellationToken cancellationToken = default)
    {
        if (_isInMemoryDatabase)
        {
            return Task.FromResult<IDbContextTransaction>(new NoOpDbContextTransaction());
        }
        return _context.Database.BeginTransactionAsync(isolationLevel, cancellationToken);
    }
}

Installation

dotnet add package EfCore.InMemory.Transactions

Or via Package Manager:

Install-Package EfCore.InMemory.Transactions

Quick Start

Step 1: Configure Test DbContext

// In CustomWebApplicationFactory.cs or test setup:
services.AddDbContext<AppDbContext>(options =>
{
    options.UseInMemoryDatabase(Guid.NewGuid().ToString())
           .AddInMemoryTransactionSupport();  // Suppresses warnings
});

Step 2: Use Safe Transaction Methods

// In your code (works with both real DB and InMemory):
await using var transaction = await context.Database
    .BeginTransactionSafeAsync(IsolationLevel.Serializable, ct);

try
{
    // ... do work ...
    await context.SaveChangesAsync(ct);
    await transaction.CommitAsync(ct);
}
catch
{
    await transaction.RollbackAsync(ct);
    throw;
}

API Reference

Extension Methods

// Check if using InMemory provider
bool isInMemory = context.Database.IsInMemoryDatabase();

// Safe transaction methods (work with any provider)
context.Database.BeginTransactionSafe();
context.Database.BeginTransactionSafe(IsolationLevel.Serializable);
await context.Database.BeginTransactionSafeAsync(ct);
await context.Database.BeginTransactionSafeAsync(IsolationLevel.Serializable, ct);

// Suppress transaction warnings in configuration
optionsBuilder.AddInMemoryTransactionSupport();

NoOpDbContextTransaction

A no-op implementation of IDbContextTransaction for use in UnitOfWork patterns:

// Use in your UnitOfWork when InMemory is detected:
if (_isInMemoryDatabase)
{
    return new NoOpDbContextTransaction();
}

Full Example: ASP.NET Core Integration Tests

CustomWebApplicationFactory.cs

public class CustomWebApplicationFactory : WebApplicationFactory<Program>
{
    protected override void ConfigureWebHost(IWebHostBuilder builder)
    {
        builder.ConfigureServices(services =>
        {
            // Remove the real database registration
            var descriptor = services.SingleOrDefault(
                d => d.ServiceType == typeof(DbContextOptions<AppDbContext>));
            if (descriptor != null)
                services.Remove(descriptor);

            // Add InMemory database with transaction support
            services.AddDbContext<AppDbContext>(options =>
            {
                options.UseInMemoryDatabase(Guid.NewGuid().ToString())
                       .AddInMemoryTransactionSupport();
            });
        });
    }
}

UnitOfWork.cs (if using UnitOfWork pattern)

using EfCore.InMemory.Transactions;

public class UnitOfWork : IUnitOfWork
{
    private readonly AppDbContext _context;
    private readonly bool _isInMemoryDatabase;

    public UnitOfWork(AppDbContext context)
    {
        _context = context;
        _isInMemoryDatabase = context.Database.IsInMemoryDatabase();
    }

    public async Task<IDbContextTransaction> BeginTransactionAsync(
        IsolationLevel isolationLevel = IsolationLevel.ReadCommitted,
        CancellationToken cancellationToken = default)
    {
        if (_isInMemoryDatabase)
        {
            // Return no-op transaction for InMemory provider
            return new NoOpDbContextTransaction();
        }

        return await _context.Database.BeginTransactionAsync(
            isolationLevel, cancellationToken);
    }

    // ... rest of UnitOfWork implementation
}

Compatibility

Why Not Just Use SQLite?

SQLite in-memory is a valid alternative, but:

Use this package when: You want fast tests and your transaction logic is already tested elsewhere.

Use SQLite when: You need real transaction semantics in tests.

How It Works

1. IsInMemoryDatabase() - Checks if the provider name contains "InMemory"
2. BeginTransactionSafeAsync() - Returns NoOpDbContextTransaction for InMemory, real transaction otherwise
3. NoOpDbContextTransaction - Implements IDbContextTransaction with no-op Commit/Rollback/Dispose
4. AddInMemoryTransactionSupport() - Suppresses TransactionIgnoredWarning

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

• Inspired by the common pain point discussed in EF Core Issue #2866
• Created to solve real-world testing challenges with EF Core InMemory provider