README.md

TransientContext

TransientContext is a simple tool for creating transient or disposable databases for integration testing. During integration testing TransientContext can be used to create a disposable database from an existing schema and drop the database after tests are complete. TransientContext supports PostgreSQL and SQLite databases.

Packages

• Current Version: 1.2.0
• Target Framework: .NET Standard 2.0

Dependencies

• Npgsql
• System.Data.SQLite
• Microsoft.Extensions.Configuration

Development Dependencies

• Microsoft.EntityFrameworkCore
• Microsoft.EntityFrameworkCore.Sqlite
• Microsoft.Extensions.Configuration.Json
• Microsoft.Extensions.Configuration.UserSecrets
• Microsoft.NET.Test.Sdk
• Npgsql.EntityFrameworkCore.PostgreSQL
• Xunit
• Xunit.runner.visualstudio
• NUnit
• NUnit3TestAdapter

Examples and Usage

The examples below are taken directly from TransientContext.Tests.NUnit and TransientContext.Tests.Xunit. In the PostgreSQL examples connection strings are stored in user secrets files as described in the Microsoft documentation.

NUnit Usage

1. Begin by creating a database fixture. In the example below, DomainContext represents the EntityFramework DBContext that is being created. For reference, see TransientContext.Tests.NUnit/Common/Data/DomainContext.cs.

    public class DatabaseFixture : IDisposable
    {
        public DatabaseFixture()
        {
            var configuration = new ConfigurationBuilder()
                .AddUserSecrets("your-secret-guid")
                .Build();
   
            TestDatabase = new TestDatabaseBuilder()
                .WithConfiguration(configuration)
                .Build();
    		
    		/* Or for SQLite 
    		 * 
        	 * TestDatabase = new TestDatabaseBuilder()
             *     .WithConnectionString("Data Source=domain.db")
             *      .Build();
             */
   
            TestDatabase.Create();
   
            var builder = new DbContextOptionsBuilder<DomainContext>()
                .UseNpgsql(TestDatabase.ConnectionString);
            DbContext = new DomainContext(builder.Options);
            DbContext.Database.EnsureCreated();
        }
    
        public ITestDatabase TestDatabase { get; }
        public DomainContext DbContext { get;  }
    
        public void Dispose()
        {
            TestDatabase.Drop();
        }
    }
   

2. Add the DatabaseFixture as part of the SetUp and TearDown methods in your test fixtures.

    [TestFixture]
    public class DomainContextTests
    {
        private DatabaseFixture _fixture;
        private DomainContext _domainContext;
   
        [SetUp]
        public void Setup()
        {
            _fixture = new DatabaseFixture();
            _domainContext = _fixture.DbContext;
        }
   
        [TearDown]
        public void Teardown()
        {
            _fixture.Dispose();
        }
   
        private async Task<User> AddEntity()
        {
            var entity = await _domainContext.Users.AddAsync(new User
            {
                Username = "Alice"
            });
            await _domainContext.SaveChangesAsync();
            return entity.Entity;
        }
   
        [Test]
        public async Task should_add_entity()
        {
            var user = await AddEntity();
   
            var count = await _domainContext.Users.CountAsync();
            Assert.NotNull(user.Id);
            Assert.AreEqual(1, count);
        }
    }
   

XUnit Usage

The examples below assume XUnit as the testing framework. These examples are taken directly from TransientContext.Tests.Xunit.

1. Begin by creating a database fixture. In the example below, DomainContext represents the EntityFramework DBContext that is being created. For reference, see TransientContext.Tests.NUnit/Common/Data/DomainContext.cs.

    public class DatabaseFixture : IDisposable
    {
        public DatabaseFixture()
        {
            var configuration = new ConfigurationBuilder()
               .AddUserSecrets("your-secret-guid")
                .Build();
            TestDatabase = new TestDatabaseBuilder()
                .WithConfiguration(configuration)
                .Build();
            TestDatabase.Create();
   
            var builder = new DbContextOptionsBuilder<DomainContext>();
            builder.UseNpgsql(TestDatabase.ConnectionString);
            DbContext = new DomainContext(builder.Options);
            DbContext.Database.EnsureCreated();
        }
   
   
        public ITestDatabase TestDatabase { get; }
   
        public DomainContext DbContext { get; }
   
        public void Dispose()
        {
            TestDatabase.Drop();
        }
    }
   
    [CollectionDefinition("Database")]
    public class DatabaseCollectionFixture : ICollectionFixture<DatabaseFixture>
    {
    }
   

2. Add the DatabaseFixture as part of a test class constructor.

    [Collection("Database")]
    public class UserTests
    {
    	private readonly TestDbContext _testDbContext;
   
    	public UserTests(DatabaseFixture databaseFixture)
    	{
    		_testDbContext = databaseFixture.DbContext;
    	}
   
    	[Fact]
    	public async Task InsertUsers()
    	{
    		await _testDbContext.Users.AddAsync(new User {Username = "Alice"});
    		await _testDbContext.Users.AddAsync(new User {Username = "Jane"});
    		await _testDbContext.SaveChangesAsync();
   
    		var count = await _testDbContext.Users.CountAsync();
    		Assert.Equal(2, count);
    	}
    }