chore: Add missing test

Author: HofmeisterAn

src/Testcontainers/Configurations/Containers/ConnectionStringProvider.cs

@@ -1,6 +1,5 @@
 namespace DotNet.Testcontainers.Configurations
 {
-  using System;
   using DotNet.Testcontainers.Containers;
 
   /// <inheritdoc cref="IConnectionStringProvider{TContainerEntity, TConfigurationEntity}" />
@@ -22,17 +21,7 @@ public ConnectionStringProvider(IConnectionStringProvider<TContainerEntity, TCon
     /// <inheritdoc />
     public void Configure(IContainer container, IContainerConfiguration configuration)
     {
-      if (container is not TContainerEntity typedContainer)
-      {
-        throw new InvalidCastException($"Expected container type '{typeof(TContainerEntity).FullName}', but received '{container.GetType().FullName}'.");
-      }
-
-      if (configuration is not TConfigurationEntity typedConfiguration)
-      {
-        throw new InvalidCastException($"Expected configuration type '{typeof(TConfigurationEntity).FullName}', but received '{configuration.GetType().FullName}'.");
-      }
-
-      _connectionStringProvider.Configure(typedContainer, typedConfiguration);
+      _connectionStringProvider.Configure((TContainerEntity)container, (TConfigurationEntity)configuration);
     }
 
     /// <inheritdoc />

tests/Testcontainers.Platform.Linux.Tests/ConnectionStringProviderTest.cs

@@ -1,40 +1,70 @@
 namespace Testcontainers.Tests;
 
-public sealed class ConnectionStringProviderTests : IAsyncLifetime
+public static class ConnectionStringProviderTests
 {
     private const string ExpectedConnectionString = "connection string";
 
-    private readonly ConnectionStringProvider _connectionStringProvider = new ConnectionStringProvider();
+    public sealed class Configured : IAsyncLifetime
+    {
+        private readonly ConnectionStringProvider _connectionStringProvider = new ConnectionStringProvider();
+
+        private readonly IContainer _container;
 
-    private readonly IContainer _container;
+        public Configured()
+        {
+            _container = new ContainerBuilder()
+                .WithImage(CommonImages.Alpine)
+                .WithCommand(CommonCommands.SleepInfinity)
+                .WithConnectionStringProvider(_connectionStringProvider)
+                .Build();
+        }
+
+        public async ValueTask InitializeAsync()
+        {
+            await _container.StartAsync()
+                .ConfigureAwait(false);
+        }
+
+        public async ValueTask DisposeAsync()
+        {
+            await _container.DisposeAsync()
+                .ConfigureAwait(false);
+        }
+
+        [Fact]
+        public void GetConnectionStringReturnsExpectedValue()
+        {
+            Assert.True(_connectionStringProvider.IsConfigured, "Configure should have been called during container startup.");
+            Assert.Equal(ExpectedConnectionString, _container.GetConnectionString());
+            Assert.Equal(ExpectedConnectionString, _container.GetConnectionString("name"));
+        }
+    }
 
-    public ConnectionStringProviderTests()
+    public sealed class NotConfigured : IAsyncLifetime
     {
-        _container = new ContainerBuilder()
+        private readonly IContainer _container = new ContainerBuilder()
             .WithImage(CommonImages.Alpine)
             .WithCommand(CommonCommands.SleepInfinity)
-            .WithConnectionStringProvider(_connectionStringProvider)
             .Build();
-    }
 
-    public async ValueTask InitializeAsync()
-    {
-        await _container.StartAsync()
-            .ConfigureAwait(false);
-    }
+        public async ValueTask InitializeAsync()
+        {
+            await _container.StartAsync()
+                .ConfigureAwait(false);
+        }
 
-    public async ValueTask DisposeAsync()
-    {
-        await _container.DisposeAsync()
-            .ConfigureAwait(false);
-    }
+        public async ValueTask DisposeAsync()
+        {
+            await _container.DisposeAsync()
+                .ConfigureAwait(false);
+        }
 
-    [Fact]
-    public void GetConnectionStringReturnsExpectedValue()
-    {
-        Assert.True(_connectionStringProvider.IsConfigured, "Configure should have been called during container startup.");
-        Assert.Equal(ExpectedConnectionString, _container.GetConnectionString());
-        Assert.Equal(ExpectedConnectionString, _container.GetConnectionString("name"));
+        [Fact]
+        public void GetConnectionStringThrowsException()
+        {
+            Assert.Throws<ConnectionStringProviderNotConfiguredException>(() => _container.GetConnectionString());
+            Assert.Throws<ConnectionStringProviderNotConfiguredException>(() => _container.GetConnectionString("name"));
+        }
     }
 
     private sealed class ConnectionStringProvider : IConnectionStringProvider<IContainer, IContainerConfiguration>