feat: added the Echo Store. (#807)

Author: Thijs153

docs/Stores.md

@@ -272,3 +272,21 @@ services.AddMultiTenant<TenantInfo>()
 services.AddMultiTenant<TenantInfo>()
         .WithDistributedCacheStore(TimeSpan.FromMinutes(5));
 ```
+
+## Echo Store
+
+> NuGet package: Finbuckle.MultiTenant
+
+The Echo Store serves as a simple, read-only store that directly returns a new tenant instance based on the given identifier
+without any additional settings. It's particularly suited for applications that require a simple, immediate method for tenant identification without the need for persistence, such as during testing phases or in environments where tenant information is static and predefined elsewhere.
+
+
+This store is read-only and calls to `TryAddAsync`, `TryUpdateAsync`, and `TryRemoveAsync` will throw
+a `NotImplementedException`. Because no stores are saved, a call to `GetAllAsync` will also throw an Exception.
+
+Configure by calling `WithEchoStore` after `AddMultiTenant<TTenantInfo>`.
+
+```csharp
+services.AddMultiTenant<TenantInfo>()
+    .WithEchoStore();
+```

src/Finbuckle.MultiTenant/DependencyInjection/MultiTenantBuilderExtensions.cs

@@ -5,6 +5,7 @@
 using Finbuckle.MultiTenant.Internal;
 using Finbuckle.MultiTenant.Stores.ConfigurationStore;
 using Finbuckle.MultiTenant.Stores.DistributedCacheStore;
+using Finbuckle.MultiTenant.Stores.EchoStore;
 using Finbuckle.MultiTenant.Stores.HttpRemoteStore;
 using Finbuckle.MultiTenant.Stores.InMemoryStore;
 using Finbuckle.MultiTenant.Strategies;
@@ -116,6 +117,14 @@ public static MultiTenantBuilder<TTenantInfo> WithInMemoryStore<TTenantInfo>(thi
 
         return builder.WithStore<InMemoryStore<TTenantInfo>>(ServiceLifetime.Singleton);
     }
+    
+    /// <summary>
+    /// Adds an EchoStore to the application.
+    /// </summary>
+    /// <param name="builder">The builder instance.</param>
+    public static MultiTenantBuilder<TTenantInfo> WithEchoStore<TTenantInfo>(this MultiTenantBuilder<TTenantInfo> builder)
+        where TTenantInfo : class, ITenantInfo, new()
+        => builder.WithStore<EchoStore<TTenantInfo>>(ServiceLifetime.Singleton);
 
     /// <summary>
     /// Adds and configures a StaticStrategy to the application.

src/Finbuckle.MultiTenant/Stores/EchoStore/EchoStore.cs

@@ -0,0 +1,65 @@
+// Copyright Finbuckle LLC, Andrew White, and Contributors.
+// Refer to the solution LICENSE file for more information.
+
+// ReSharper disable once CheckNamespace
+
+using Finbuckle.MultiTenant.Abstractions;
+
+namespace Finbuckle.MultiTenant.Stores.EchoStore;
+
+/// <summary>
+/// Basic store that simply returns a tenant based on the identifier without any additional settings.
+/// Note that add, update, and remove functionality is not implemented.
+/// If underlying configuration supports reload-on-change then this store will reflect such changes.
+/// </summary>
+/// <typeparam name="TTenantInfo">The ITenantInfo implementation type.</typeparam>
+public class EchoStore<TTenantInfo> : IMultiTenantStore<TTenantInfo> where TTenantInfo : class, ITenantInfo, new()
+{
+    /// <inheritdoc />
+    public async Task<TTenantInfo?> TryGetByIdentifierAsync(string identifier)
+    {
+        return await Task.FromResult(new TTenantInfo { Id = identifier, Identifier = identifier });
+    }
+
+    /// <inheritdoc />
+    public async Task<TTenantInfo?> TryGetAsync(string id)
+    {
+        return await Task.FromResult(new TTenantInfo { Id = id, Identifier = id });
+    }
+    
+    /// <summary>
+    /// Not implemented in this implementation.
+    /// </summary>
+    /// <exception cref="NotImplementedException"></exception>
+    public Task<bool> TryAddAsync(TTenantInfo tenantInfo)
+    {
+        throw new NotImplementedException();
+    }
+
+    /// <summary>
+    /// Not implemented in this implementation.
+    /// </summary>
+    /// <exception cref="NotImplementedException"></exception>
+    public Task<bool> TryUpdateAsync(TTenantInfo tenantInfo)
+    {
+        throw new NotImplementedException();
+    }
+
+    /// <summary>
+    /// Not implemented in this implementation.
+    /// </summary>
+    /// <exception cref="NotImplementedException"></exception>
+    public Task<bool> TryRemoveAsync(string identifier)
+    {
+        throw new NotImplementedException();
+    }
+
+    /// <summary>
+    /// Not implemented in this implementation.
+    /// </summary>
+    /// <exception cref="NotImplementedException"></exception>
+    public Task<IEnumerable<TTenantInfo>> GetAllAsync()
+    {
+        throw new NotImplementedException();
+    }
+}

test/Finbuckle.MultiTenant.Test/DependencyInjection/MultiTenantBuilderExtensionsShould.cs

@@ -4,6 +4,7 @@
 using Finbuckle.MultiTenant.Abstractions;
 using Finbuckle.MultiTenant.Stores.ConfigurationStore;
 using Finbuckle.MultiTenant.Stores.DistributedCacheStore;
+using Finbuckle.MultiTenant.Stores.EchoStore;
 using Finbuckle.MultiTenant.Stores.HttpRemoteStore;
 using Finbuckle.MultiTenant.Stores.InMemoryStore;
 using Finbuckle.MultiTenant.Strategies;
@@ -157,6 +158,26 @@ public async Task AddInMemoryStoreWithCaseSensitivity()
         Assert.Null(tc);
     }
 
+    [Fact]
+    public async Task AddEchoStore()
+    {
+        var services = new ServiceCollection();
+        var builder = new MultiTenantBuilder<TenantInfo>(services);
+        builder.WithEchoStore();
+        var sp = services.BuildServiceProvider();
+            
+        var store = sp.GetRequiredService<IMultiTenantStore<TenantInfo>>();
+        Assert.IsType<EchoStore<TenantInfo>>(store);
+
+        var tc = await store.TryGetByIdentifierAsync("initech");
+        Assert.Equal("initech", tc!.Id);
+        Assert.Equal("initech", tc.Identifier);
+
+        tc = await store.TryGetByIdentifierAsync("lol");
+        Assert.Equal("lol", tc!.Id);
+        Assert.Equal("lol", tc.Identifier);
+    }
+    
     [Fact]
     public void AddDelegateStrategy()
     {