MockAsyncEnumerable 2.0.0.6582

A simple implementation for transforming synchronous collections into async enumerables, enabling seamless testing of EF Core queries, paginated grids, and LINQ operations, or any action or dynamic aggregated query using EF Core (Microsoft.EntityFrameworkCore) through Expressions (System.Linq.Expressions) with IAsyncEnumerable<T>.

This library was born from the necessity to implement paged grid results in projects where data was provided by stored procedures or in-memory collections, while still needing to support async EF Core APIs like ToListAsync(), FirstOrDefaultAsync(), etc.

Features

• Convert IEnumerable<T>, IQueryable<T>, and arrays to IAsyncEnumerable<T>;
• Builder pattern for fluent async enumerable construction;
• Factory methods for quick creation (Empty, Single, Create);
• Full support for LINQ async operations (Where, Select, OrderBy, etc.);
• Comprehensive null guards and error handling;
• Proper cancellation token support;
• Optimized disposal patterns (IAsyncDisposable);
• Extensive test coverage;
• Compatible with EF Core testing scenarios;

Installation

In case you wish to use it in your project, u can install the package from <a href="https://www.nuget.org/packages/MockAsyncEnumerable" target="_blank">nuget.org</a> or specify what version you want:

Install-Package MockAsyncEnumerable

Or specify a version:

Install-Package MockAsyncEnumerable -Version x.x.x.x

Examples

Using Extension Methods

using MockAsyncEnumerable.Extensions;
using Microsoft.EntityFrameworkCore;

// Convert a list to async enumerable
var users = new List<User>
{
    new User { Id = 1, Name = "Alice" },
    new User { Id = 2, Name = "Bob" }
};

var asyncUsers = users.ToMockAsyncEnumerable();
var result = await asyncUsers.Where(u => u.Id > 1).ToListAsync();

Using Factory Methods

using MockAsyncEnumerable;
using Microsoft.EntityFrameworkCore;

// Create empty async enumerable
var empty = AsyncEnumerableFactory.Empty<User>();

// Create from single item
var single = AsyncEnumerableFactory.Single(new User { Id = 1, Name = "Alice" });

// Create from multiple items
var multiple = AsyncEnumerableFactory.Create(
    new User { Id = 1, Name = "Alice" },
    new User { Id = 2, Name = "Bob" }
);

var users = await multiple.ToListAsync();

Using Builder Pattern

using MockAsyncEnumerable;
using Microsoft.EntityFrameworkCore;

// Build an async enumerable fluently
var users = AsyncEnumerableFactory.Builder<User>()
    .Add(new User { Id = 1, Name = "Alice" })
    .Add(new User { Id = 2, Name = "Bob" })
    .AddRange(moreUsers)
    .Build();

var result = await users.ToListAsync();

Using EnumerableInvoker

using MockAsyncEnumerable;
using Microsoft.EntityFrameworkCore;

var data = new List<User>
{
    new User { Id = 1, Name = "Alice" },
    new User { Id = 2, Name = "Bob" }
};

var asyncEnumerable = EnumerableInvoker.Invoke(data);
var result = await asyncEnumerable.FirstOrDefaultAsync(u => u.Name == "Alice");

API Reference

Extension Methods (MockAsyncEnumerable.Extensions)

Factory Methods (AsyncEnumerableFactory)

Builder Pattern (AsyncEnumerableBuilder<T>)

Classic Approach (EnumerableInvoker)