Introduce a new IDatabaseContainer interface

This is required in order to implement a generic database fixture that could look like this.

```csharp
using System;
using System.Data.Common;
using System.Threading.Tasks;
using DotNet.Testcontainers.Builders;
using DotNet.Testcontainers.Containers;
using Testcontainers.MsSql;
using Testcontainers.MySql;
using Testcontainers.PostgreSql;
using Xunit;

namespace SampleCode;

public abstract class DatabaseFixture<TBuilder, TContainer> : IAsyncLifetime
    where TBuilder : IContainerBuilder<TBuilder, TContainer>, new()
    where TContainer : IContainer, IDatabaseContainer
{
    private string _connectionString;
    private TContainer _container;

    protected abstract DbProviderFactory ProviderFactory { get; }

    public string ConnectionString => _connectionString ?? throw new InvalidOperationException($"{nameof(IAsyncLifetime.InitializeAsync)} must be called before accessing the connection string");

    async Task IAsyncLifetime.InitializeAsync()
    {
        _container = new TBuilder().Build();
        await _container.StartAsync();
        _connectionString = _container.GetConnectionString();
        using var connection = ProviderFactory.CreateConnection() ?? throw new InvalidOperationException($"ProviderFactory.CreateConnection() returned null ({ProviderFactory})");
        connection.ConnectionString = _connectionString;
        await connection.OpenAsync();
        await connection.CloseAsync();
    }

    async Task IAsyncLifetime.DisposeAsync()
    {
        if (_container != null)
        {
            await _container.StopAsync();
        }
    }
}

public class MsSqlDbFixture : DatabaseFixture<MsSqlBuilder, MsSqlContainer>
{
    protected override DbProviderFactory ProviderFactory => Microsoft.Data.SqlClient.SqlClientFactory.Instance;
}

public class MySqlDbFixture : DatabaseFixture<MySqlBuilder, MySqlContainer>
{
    protected override DbProviderFactory ProviderFactory => MySqlConnector.MySqlConnectorFactory.Instance;
}

public class PostgreSqlDbFixture : DatabaseFixture<PostgreSqlBuilder, PostgreSqlContainer>
{
    protected override DbProviderFactory ProviderFactory => Npgsql.NpgsqlFactory.Instance;
}

public class PostgreSqlTest : IClassFixture<PostgreSqlDbFixture>
{
    private readonly PostgreSqlDbFixture _dbFixture;

    public PostgreSqlTest(PostgreSqlDbFixture dbFixture) => _dbFixture = dbFixture;

    [Fact]
    public async Task TestOnPostgreSql()
    {
        await using var connection = new Npgsql.NpgsqlConnection(_dbFixture.ConnectionString);
        await using var command = connection.CreateCommand();

        // ...
    }
}
```

This will also be required to implement a new wait strategy for database where an ADO.NET provider is available.

Testcontainers.sln

@@ -137,6 +137,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Testcontainers.Tests", "tes
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Testcontainers.WebDriver.Tests", "tests\Testcontainers.WebDriver.Tests\Testcontainers.WebDriver.Tests.csproj", "{EBA72C3B-57D5-43FF-A5B4-3D55B3B6D4C2}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Testcontainers.Databases.Tests", "tests\Testcontainers.Databases.Tests\Testcontainers.Databases.Tests.csproj", "{DA54916E-1128-4200-B6AE-9F5BF02D832D}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -394,6 +396,10 @@ Global
 		{EBA72C3B-57D5-43FF-A5B4-3D55B3B6D4C2}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{EBA72C3B-57D5-43FF-A5B4-3D55B3B6D4C2}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{EBA72C3B-57D5-43FF-A5B4-3D55B3B6D4C2}.Release|Any CPU.Build.0 = Release|Any CPU
+		{DA54916E-1128-4200-B6AE-9F5BF02D832D}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{DA54916E-1128-4200-B6AE-9F5BF02D832D}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{DA54916E-1128-4200-B6AE-9F5BF02D832D}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{DA54916E-1128-4200-B6AE-9F5BF02D832D}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(NestedProjects) = preSolution
 		{3F2E254F-C203-43FD-A078-DC3E2CBC0F9F} = {673F23AE-7694-4BB9-ABD4-136D6C13634E}
@@ -458,5 +464,6 @@ Global
 		{1A1983E6-5297-435F-B467-E8E1F11277D6} = {7164F1FB-7F24-444A-ACD2-2C329C2B3CCF}
 		{27CDB869-A150-4593-958F-6F26E5391E7C} = {7164F1FB-7F24-444A-ACD2-2C329C2B3CCF}
 		{EBA72C3B-57D5-43FF-A5B4-3D55B3B6D4C2} = {7164F1FB-7F24-444A-ACD2-2C329C2B3CCF}
+		{DA54916E-1128-4200-B6AE-9F5BF02D832D} = {7164F1FB-7F24-444A-ACD2-2C329C2B3CCF}
 	EndGlobalSection
 EndGlobal

src/Testcontainers.Azurite/AzuriteContainer.cs

@@ -2,7 +2,7 @@ namespace Testcontainers.Azurite;
 
 /// <inheritdoc cref="DockerContainer" />
 [PublicAPI]
-public sealed class AzuriteContainer : DockerContainer
+public sealed class AzuriteContainer : DockerContainer, IDatabaseContainer
 {
     private const string AccountName = "devstoreaccount1";
 

src/Testcontainers.CosmosDb/CosmosDbContainer.cs

@@ -2,7 +2,7 @@ namespace Testcontainers.CosmosDb;
 
 /// <inheritdoc cref="DockerContainer" />
 [PublicAPI]
-public sealed class CosmosDbContainer : DockerContainer
+public sealed class CosmosDbContainer : DockerContainer, IDatabaseContainer
 {
     /// <summary>
     /// Initializes a new instance of the <see cref="CosmosDbContainer" /> class.

src/Testcontainers.CouchDb/CouchDbContainer.cs

@@ -2,7 +2,7 @@ namespace Testcontainers.CouchDb;
 
 /// <inheritdoc cref="DockerContainer" />
 [PublicAPI]
-public sealed class CouchDbContainer : DockerContainer
+public sealed class CouchDbContainer : DockerContainer, IDatabaseContainer
 {
     private readonly CouchDbConfiguration _configuration;
 

src/Testcontainers.Couchbase/CouchbaseContainer.cs

@@ -2,7 +2,7 @@ namespace Testcontainers.Couchbase;
 
 /// <inheritdoc cref="DockerContainer" />
 [PublicAPI]
-public sealed class CouchbaseContainer : DockerContainer
+public sealed class CouchbaseContainer : DockerContainer, IDatabaseContainer
 {
     private readonly CouchbaseConfiguration _configuration;
 

src/Testcontainers.DynamoDb/DynamoDbContainer.cs

@@ -2,7 +2,7 @@ namespace Testcontainers.DynamoDb;
 
 /// <inheritdoc cref="DockerContainer" />
 [PublicAPI]
-public sealed class DynamoDbContainer : DockerContainer
+public sealed class DynamoDbContainer : DockerContainer, IDatabaseContainer
 {
     /// <summary>
     /// Initializes a new instance of the <see cref="DynamoDbContainer" /> class.

src/Testcontainers.Elasticsearch/ElasticsearchContainer.cs

@@ -2,7 +2,7 @@ namespace Testcontainers.Elasticsearch;
 
 /// <inheritdoc cref="DockerContainer" />
 [PublicAPI]
-public sealed class ElasticsearchContainer : DockerContainer
+public sealed class ElasticsearchContainer : DockerContainer, IDatabaseContainer
 {
     private readonly ElasticsearchConfiguration _configuration;
 

src/Testcontainers.EventStoreDb/EventStoreDbContainer.cs

@@ -2,7 +2,7 @@ namespace Testcontainers.EventStoreDb;
 
 /// <inheritdoc cref="DockerContainer" />
 [PublicAPI]
-public sealed class EventStoreDbContainer : DockerContainer
+public sealed class EventStoreDbContainer : DockerContainer, IDatabaseContainer
 {
     /// <summary>
     /// Initializes a new instance of the <see cref="EventStoreDbContainer" /> class.

src/Testcontainers.LocalStack/LocalStackContainer.cs

@@ -2,7 +2,7 @@ namespace Testcontainers.LocalStack;
 
 /// <inheritdoc cref="DockerContainer" />
 [PublicAPI]
-public sealed class LocalStackContainer : DockerContainer
+public sealed class LocalStackContainer : DockerContainer, IDatabaseContainer
 {
     /// <summary>
     /// Initializes a new instance of the <see cref="LocalStackContainer" /> class.

src/Testcontainers.MariaDb/MariaDbContainer.cs

@@ -2,7 +2,7 @@ namespace Testcontainers.MariaDb;
 
 /// <inheritdoc cref="DockerContainer" />
 [PublicAPI]
-public sealed class MariaDbContainer : DockerContainer
+public sealed class MariaDbContainer : DockerContainer, IDatabaseContainer
 {
     private readonly MariaDbConfiguration _configuration;
 

src/Testcontainers.Minio/MinioContainer.cs

@@ -2,7 +2,7 @@ namespace Testcontainers.Minio;
 
 /// <inheritdoc cref="DockerContainer" />
 [PublicAPI]
-public sealed class MinioContainer : DockerContainer
+public sealed class MinioContainer : DockerContainer, IDatabaseContainer
 {
     private readonly MinioConfiguration _configuration;
 

src/Testcontainers.MongoDb/MongoDbContainer.cs

@@ -2,7 +2,7 @@ namespace Testcontainers.MongoDb;
 
 /// <inheritdoc cref="DockerContainer" />
 [PublicAPI]
-public sealed class MongoDbContainer : DockerContainer
+public sealed class MongoDbContainer : DockerContainer, IDatabaseContainer
 {
     private readonly MongoDbConfiguration _configuration;
 

src/Testcontainers.MsSql/MsSqlContainer.cs

@@ -2,7 +2,7 @@ namespace Testcontainers.MsSql;
 
 /// <inheritdoc cref="DockerContainer" />
 [PublicAPI]
-public sealed class MsSqlContainer : DockerContainer
+public sealed class MsSqlContainer : DockerContainer, IDatabaseContainer
 {
     private readonly MsSqlConfiguration _configuration;
 

src/Testcontainers.MySql/MySqlContainer.cs

@@ -2,7 +2,7 @@ namespace Testcontainers.MySql;
 
 /// <inheritdoc cref="DockerContainer" />
 [PublicAPI]
-public sealed class MySqlContainer : DockerContainer
+public sealed class MySqlContainer : DockerContainer, IDatabaseContainer
 {
     private readonly MySqlConfiguration _configuration;
 

src/Testcontainers.Neo4j/Neo4jContainer.cs

@@ -2,7 +2,7 @@ namespace Testcontainers.Neo4j;
 
 /// <inheritdoc cref="DockerContainer" />
 [PublicAPI]
-public sealed class Neo4jContainer : DockerContainer
+public sealed class Neo4jContainer : DockerContainer, IDatabaseContainer
 {
     /// <summary>
     /// Initializes a new instance of the <see cref="Neo4jContainer" /> class.

src/Testcontainers.Oracle/OracleContainer.cs

@@ -2,7 +2,7 @@ namespace Testcontainers.Oracle;
 
 /// <inheritdoc cref="DockerContainer" />
 [PublicAPI]
-public sealed class OracleContainer : DockerContainer
+public sealed class OracleContainer : DockerContainer, IDatabaseContainer
 {
     private readonly OracleConfiguration _configuration;
 

src/Testcontainers.PostgreSql/PostgreSqlContainer.cs

@@ -2,7 +2,7 @@ namespace Testcontainers.PostgreSql;
 
 /// <inheritdoc cref="DockerContainer" />
 [PublicAPI]
-public sealed class PostgreSqlContainer : DockerContainer
+public sealed class PostgreSqlContainer : DockerContainer, IDatabaseContainer
 {
     private readonly PostgreSqlConfiguration _configuration;
 

src/Testcontainers.RabbitMq/RabbitMqContainer.cs

@@ -2,7 +2,7 @@ namespace Testcontainers.RabbitMq;
 
 /// <inheritdoc cref="DockerContainer" />
 [PublicAPI]
-public sealed class RabbitMqContainer : DockerContainer
+public sealed class RabbitMqContainer : DockerContainer, IDatabaseContainer
 {
     private readonly RabbitMqConfiguration _configuration;
 

src/Testcontainers.RavenDb/RavenDbContainer.cs

@@ -2,7 +2,7 @@ namespace Testcontainers.RavenDb;
 
 /// <inheritdoc cref="DockerContainer" />
 [PublicAPI]
-public sealed class RavenDbContainer : DockerContainer
+public sealed class RavenDbContainer : DockerContainer, IDatabaseContainer
 {
     /// <summary>
     /// Initializes a new instance of the <see cref="RavenDbContainer" /> class.

src/Testcontainers.Redis/RedisContainer.cs

@@ -2,7 +2,7 @@ namespace Testcontainers.Redis;
 
 /// <inheritdoc cref="DockerContainer" />
 [PublicAPI]
-public sealed class RedisContainer : DockerContainer
+public sealed class RedisContainer : DockerContainer, IDatabaseContainer
 {
     /// <summary>
     /// Initializes a new instance of the <see cref="RedisContainer" /> class.

src/Testcontainers.SqlEdge/SqlEdgeContainer.cs

@@ -2,7 +2,7 @@ namespace Testcontainers.SqlEdge;
 
 /// <inheritdoc cref="DockerContainer" />
 [PublicAPI]
-public sealed class SqlEdgeContainer : DockerContainer
+public sealed class SqlEdgeContainer : DockerContainer, IDatabaseContainer
 {
     private readonly SqlEdgeConfiguration _configuration;
 

src/Testcontainers.WebDriver/WebDriverContainer.cs

@@ -2,7 +2,7 @@ namespace Testcontainers.WebDriver;
 
 /// <inheritdoc cref="DockerContainer" />
 [PublicAPI]
-public sealed class WebDriverContainer : DockerContainer
+public sealed class WebDriverContainer : DockerContainer, IDatabaseContainer
 {
     private readonly WebDriverConfiguration _configuration;
 

src/Testcontainers/Containers/IDatabaseContainer.cs

@@ -0,0 +1,17 @@
+namespace DotNet.Testcontainers.Containers
+{
+  using JetBrains.Annotations;
+
+  /// <summary>
+  /// A database container instance.
+  /// </summary>
+  [PublicAPI]
+  public interface IDatabaseContainer
+  {
+    /// <summary>
+    /// Gets the connection string for connecting to the database.
+    /// </summary>
+    /// <returns>The connection string for connecting to the database.</returns>
+    string GetConnectionString();
+  }
+}

tests/Testcontainers.Databases.Tests/.editorconfig

@@ -0,0 +1 @@
+root = true

tests/Testcontainers.Databases.Tests/DatabasesContainerTest.cs

@@ -0,0 +1,25 @@
+namespace Testcontainers.Databases;
+
+public sealed class DatabaseContainersTest
+{
+    [Theory]
+    [MemberData(nameof(DatabaseContainersTheoryData))]
+    public void ImplementsIDatabaseContainerInterface(Type type)
+    {
+        Assert.True(type.IsAssignableTo(typeof(IDatabaseContainer)));
+    }
+
+    public static IEnumerable<object[]> DatabaseContainersTheoryData
+    {
+        get
+        {
+            static bool HasGetConnectionStringMethod(Type type) => type.IsAssignableTo(typeof(IContainer)) && type.GetMethod("GetConnectionString") != null;
+            var assembly = typeof(DatabaseContainersTest).Assembly;
+            var dependencyContext = DependencyContext.Load(assembly) ?? throw new InvalidOperationException($"DependencyContext.Load({assembly}) returned null");
+            return dependencyContext.RuntimeLibraries
+                .Where(library => library.Name.StartsWith("Testcontainers."))
+                .SelectMany(library => Assembly.Load(library.Name).GetExportedTypes().Where(HasGetConnectionStringMethod))
+                .Select(type => new[] { type });
+        }
+    }
+}

tests/Testcontainers.Databases.Tests/Testcontainers.Databases.Tests.csproj

@@ -0,0 +1,17 @@
+<Project Sdk="Microsoft.NET.Sdk">
+    <PropertyGroup>
+        <TargetFrameworks>net6.0</TargetFrameworks>
+        <IsPackable>false</IsPackable>
+        <IsPublishable>false</IsPublishable>
+    </PropertyGroup>
+    <ItemGroup>
+        <PackageReference Include="Microsoft.Extensions.DependencyModel" Version="7.0.0" />
+        <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.4.1" />
+        <PackageReference Include="coverlet.collector" Version="3.2.0" />
+        <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5" />
+        <PackageReference Include="xunit" Version="2.4.2" />
+    </ItemGroup>
+    <ItemGroup>
+        <ProjectReference Include="$(SolutionDir)src/Testcontainers.*/Testcontainers.*.csproj" />
+    </ItemGroup>
+</Project>

tests/Testcontainers.Databases.Tests/Usings.cs

@@ -0,0 +1,7 @@
+global using System;
+global using System.Collections.Generic;
+global using System.Linq;
+global using System.Reflection;
+global using DotNet.Testcontainers.Containers;
+global using Microsoft.Extensions.DependencyModel;
+global using Xunit;