EntityFrameworkMock

Easy Mock wrapper for mocking EF6 DbContext and DbSet using Moq

Get it on NuGet

PM> Install-Package EntityFrameworkMock

Description

This library contains a DbContext and DbSet wrapper based on the Moq framework.

It emulates the following EF behavior:

• Only save entity updates/inserts/delete when SaveChanges or SaveChangesAsync is called
• Supports auto-increment identity columns with the [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)] attributes
• Supports primary key on multiple columns with the [Key, Column(Order = X)] attributes
• Throws a DbUpdateException when inserting 2 or more entities with the same primary key while calling SaveChanges / SaveChangesAsync
• Throws a DbUpdateConcurrencyException when removing a model that no longer exists

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

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(string connectionString)
        : base(connectionString)
    {
    }

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

[TestFixture]
public class MyTests
{
    var initialEntities = new[]
        {
            new User { Id = Guid.NewGuid(), FullName = "Eric Cartoon" },
            new User { Id = Guid.NewGuid(), FullName = "Billy Jewel" },
        };
        
    var dbContextMock = new DbContextMock<TestDbContext>("fake connectionstring");
    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);
}