chore: Refactor tests

Author: HofmeisterAn

tests/Testcontainers.Tests/Unit/Configurations/UntilHostTcpPortIsAvailableTest.cs

@@ -0,0 +1,75 @@
+namespace DotNet.Testcontainers.Tests.Unit
+{
+  using System;
+  using System.Threading.Tasks;
+  using DotNet.Testcontainers.Builders;
+  using DotNet.Testcontainers.Commons;
+  using DotNet.Testcontainers.Configurations;
+  using DotNet.Testcontainers.Containers;
+  using Xunit;
+
+  public sealed class WaitUntilExternalTcpPortIsAvailable : IAsyncLifetime
+  {
+    private const ushort ListeningPort = 49152;
+
+    private const ushort MappedPort = 49153;
+
+    private const ushort UnmappedPort = 49154;
+
+    private readonly IContainer _container = new ContainerBuilder()
+      .WithImage(CommonImages.Socat)
+      .WithCommand("-v")
+      .WithCommand($"TCP-LISTEN:{ListeningPort},crlf,reuseaddr,fork")
+      .WithCommand("EXEC:cat")
+      .WithPortBinding(ListeningPort, true)
+      .WithPortBinding(MappedPort, true)
+      .WithWaitStrategy(Wait.ForUnixContainer().UntilExternalTcpPortIsAvailable(ListeningPort))
+      .Build();
+
+    public async ValueTask InitializeAsync()
+    {
+      await _container.StartAsync()
+        .ConfigureAwait(false);
+    }
+
+    public ValueTask DisposeAsync()
+    {
+      return _container.DisposeAsync();
+    }
+
+    [Fact]
+    public async Task SucceedsWhenPortIsMappedAndListening()
+    {
+      // Given
+      var waitStrategy = new UntilExternalTcpPortIsAvailable(ListeningPort);
+
+      // When
+      var success = await waitStrategy.UntilAsync(_container)
+        .ConfigureAwait(true);
+
+      // Then
+      Assert.True(success);
+    }
+
+    [Fact]
+    public async Task SucceedsWhenPortIsMappedButNotListening()
+    {
+      // Given
+      var waitStrategy = new UntilExternalTcpPortIsAvailable(MappedPort);
+
+      // When
+      var success = await waitStrategy.UntilAsync(_container)
+        .ConfigureAwait(true);
+
+      // Then
+      Assert.True(success);
+    }
+
+    [Fact]
+    public Task ThrowsWhenPortIsNotMapped()
+    {
+      var waitStrategy = new UntilExternalTcpPortIsAvailable(UnmappedPort);
+      return Assert.ThrowsAsync<InvalidOperationException>(() => waitStrategy.UntilAsync(_container));
+    }
+  }
+}