Add integration tests for required ports functionality.

Author: christophergunn

DockerComposeFixture.Tests/IntegrationTests.cs

@@ -42,6 +42,8 @@ public async Task EchoServer_SaysHello_WhenCalled()
             Assert.Contains("hello world", response);
         }
 
+        
+        
         public void Dispose()
         {
             File.Delete(this.dockerComposeFile);

DockerComposeFixture.Tests/RequiredPortsIntegrationTests.cs

@@ -0,0 +1,82 @@
+using System;
+using System.IO;
+using System.Linq;
+using System.Net;
+using System.Net.Sockets;
+using DockerComposeFixture.Exceptions;
+using Xunit;
+
+namespace DockerComposeFixture.Tests;
+
+public class RequiredPortsIntegrationTests : IClassFixture<DockerFixture>, IDisposable
+{
+    private readonly DockerFixture dockerFixture;
+    private readonly string dockerComposeFile;
+
+    private const string DockerCompose = @"
+version: '3.4'
+services:
+    echo_server:
+        image: hashicorp/http-echo
+        ports:
+        - 12871:8080
+        command: -listen=:8080 -text=""hello world""
+        ";
+    
+    public RequiredPortsIntegrationTests(DockerFixture dockerFixture)
+    {
+        this.dockerFixture = dockerFixture;
+        this.dockerComposeFile = Path.GetTempFileName();
+        File.WriteAllText(this.dockerComposeFile, DockerCompose);
+    }
+
+    [Fact]
+    public void Ports_DetermineUtilizedPorts_ReturnsThoseInUse()
+    {
+        // Arrange
+        const ushort portToOccupy = 12871;
+        var ipEndPoint = new IPEndPoint(IPAddress.Loopback, portToOccupy);
+        using Socket listener = new(
+            ipEndPoint.AddressFamily,
+            SocketType.Stream,
+            ProtocolType.Tcp);
+        listener.Bind(ipEndPoint);
+        listener.Listen();
+        
+        // Act
+        var usedPorts = Ports.DetermineUtilizedPorts([12870, 12871, 12872]);
+        
+        // Assert
+        Assert.Single(usedPorts, p => p == 12871);
+    }
+
+    [Fact]
+    public void GivenRequiredPortInUse_ThenExceptionIsThrownWithPortNumber()
+    {
+        const ushort portToOccupy = 12871;
+        var ipEndPoint = new IPEndPoint(IPAddress.Loopback, portToOccupy);
+        using Socket listener = new(
+            ipEndPoint.AddressFamily,
+            SocketType.Stream,
+            ProtocolType.Tcp);
+        listener.Bind(ipEndPoint);
+        listener.Listen();
+        
+        var thrownException = Assert.Throws<PortsUnavailableException>(() =>
+        {
+            dockerFixture.InitOnce(() => new DockerFixtureOptions
+            {
+                DockerComposeFiles = new[] { this.dockerComposeFile },
+                CustomUpTest = output => output.Any(l => l.Contains("server is listening")),
+                RequiredPorts = new ushort[] { portToOccupy }
+            });
+        });
+        
+        Assert.Equivalent(new ushort[] { portToOccupy }, thrownException.Ports);
+    }
+    
+    public void Dispose()
+    {
+        File.Delete(this.dockerComposeFile);
+    }
+}