EntityFrameworkCoreMock

Easy Mock wrapper for mocking EF Core 10 DbContext and DbSet in your unit-tests. Integrates with Moq or NSubstitute.

Get it on NuGet

Moq integration

PM> Install-Package EntityFrameworkCoreMock.Moq

NSubstitute integration

PM> Install-Package EntityFrameworkCoreMock.NSubstitute

Supports

• In-memory storage of test data
• Querying of in-memory test data (synchronous or asynchronous)
• Tracking of updates, inserts and deletes of in-memory test data
• Emulation of SaveChanges and SaveChangesAsync (only saves tracked changes to the mocked in-memory DbSet when one of these methods are called)
• Auto-increment identity columns, annotated by the [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)] attribute
• Primary key on multiple columns, annotated by the [Key, Column(Order = X)] attributes

TODO

• Throwing a DbUpdateException when inserting 2 or more entities with the same primary key while calling SaveChanges / SaveChangesAsync (emulating EF behavior)
• Throwing a DbUpdateConcurrencyException when removing a model that no longer exists (emulating EF behavior)

For the Moq version, you can use all known Moq features, since both DbSetMock and DbContextMock inherit from Mock<DbSet> and Mock<DbContext> respectively.

Example usage

public class User
{
    [Key, Column(Order = 0)]
    public Guid Id { get; set; }

    public string FullName { get; set; }
}

public class TestDbContext : DbContext
{
    public TestDbContext(DbContextOptions<TestDbContext> options)
        : base(options)
    {
    }

    public virtual DbSet<User> Users { get; set; }
}

public class MyTests
{
    [Fact]
    public void DbSetTest()
    {
        var initialEntities = new[]
            {
                new User { Id = Guid.NewGuid(), FullName = "Eric Cartoon" },
                new User { Id = Guid.NewGuid(), FullName = "Billy Jewel" },
            };
        
        var dbContextMock = new DbContextMock<TestDbContext>(DummyOptions);
        var usersDbSetMock = dbContextMock.CreateDbSetMock(x => x.Users, initialEntities);
    
        // Pass dbContextMock.Object to the class/method you want to test
    
        // Query dbContextMock.Object.Users to see if certain users were added or removed
        // or use Mock Verify functionality to verify if certain methods were called: usersDbSetMock.Verify(x => x.Add(...), Times.Once);
    }
}

public DbContextOptions<TestDbContext> DummyOptions { get; } = new DbContextOptionsBuilder<TestDbContext>().Options;