Implement PuppeteerLoaderFixture (#80)

This class will help us download chromium and setup a WebServer in a CI server

Author: kblok

lib/PuppeteerSharp.Tests/Page/PdfTests.cs

@@ -7,9 +7,9 @@
 
 namespace PuppeteerSharp.Tests.Page
 {
+    [Collection("PuppeteerLoaderFixture collection")]
     public class PdfTests : PuppeteerBaseTest
     {
-
         [Fact]
         public async Task ShouldBeAbleToSaveFile()
         {

lib/PuppeteerSharp.Tests/Page/ScreenshotTests.cs

@@ -8,9 +8,9 @@
 
 namespace PuppeteerSharp.Tests.Page
 {
+    [Collection("PuppeteerLoaderFixture collection")]
     public class ScreenshotTests : PuppeteerBaseTest
     {
-
         [Fact]
         public async Task ShouldWorkWithFile()
         {

lib/PuppeteerSharp.Tests/Puppeteer/PuppeteerLaunchTests.cs

@@ -3,13 +3,9 @@
 
 namespace PuppeteerSharp.Tests.Puppeteer
 {
+    [Collection("PuppeteerLoaderFixture collection")]
     public class PuppeteerLaunchTests
     {
-        public PuppeteerLaunchTests()
-        {
-            Downloader.CreateDefault().DownloadRevisionAsync(TestConstants.ChromiumRevision).GetAwaiter().GetResult();
-        }
-
         [Fact]
         public async Task ShouldSupportIgnoreHTTPSErrorsOption()
         {

lib/PuppeteerSharp.Tests/PuppeteerLoaderCollection.cs

@@ -0,0 +1,15 @@
+using System;
+using Xunit;
+
+namespace PuppeteerSharp.Tests
+{
+    [CollectionDefinition("PuppeteerLoaderFixture collection")]
+    public class DatabaseCollection : ICollectionFixture<PuppeteerLoaderFixture>
+    {
+        // This class has no code, and is never created. Its purpose is simply
+        // to be the place to apply [CollectionDefinition] and all the
+        // ICollectionFixture<> interfaces.
+        //Recipe from https://xunit.github.io/docs/shared-context.html#class-fixture
+    }
+
+}

lib/PuppeteerSharp.Tests/PuppeteerLoaderFixture.cs

@@ -0,0 +1,107 @@
+using System;
+using System.Diagnostics;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace PuppeteerSharp.Tests
+{
+    public class PuppeteerLoaderFixture : IDisposable
+    {
+        Process _webServerProcess = null;
+
+        public PuppeteerLoaderFixture()
+        {
+            SetupAsync().GetAwaiter().GetResult();
+        }
+
+        public void Dispose()
+        {
+            int processId = 0;
+
+            try
+            {
+                processId = _webServerProcess.Id;
+            }
+            catch (InvalidOperationException)
+            {
+                //We might get an InvalidOperationException if the process is in an invalid state
+            }
+            catch (Exception ex)
+            {
+                throw new Exception("Unable to kill webserver", ex);
+            }
+
+            if (processId != 0 && Process.GetProcessById(processId) != null)
+            {
+                _webServerProcess.Kill();
+            }
+
+        }
+
+        private async Task SetupAsync()
+        {
+            var downloaderTask = Downloader.CreateDefault().DownloadRevisionAsync(TestConstants.ChromiumRevision);
+            var serverTask = StartWebServerAsync();
+
+            await Task.WhenAll(downloaderTask, serverTask);
+
+        }
+
+        private async Task StartWebServerAsync()
+        {
+            var taskWrapper = new TaskCompletionSource<bool>();
+            const int timeout = 2000;
+
+            var build = Directory.GetCurrentDirectory().Contains("Debug") ? "Debug" : "Release";
+            var webServerPath = Path.Combine(Directory.GetCurrentDirectory(), "..", "..", "..", "..",
+                                             "PuppeteerSharp.TestServer");
+
+            _webServerProcess = new Process();
+            _webServerProcess.StartInfo.FileName = "dotnet";
+            _webServerProcess.StartInfo.WorkingDirectory = webServerPath;
+            _webServerProcess.StartInfo.Arguments = $"./bin/{build}/netcoreapp2.0/PuppeteerSharp.TestServer.dll";
+
+            _webServerProcess.StartInfo.RedirectStandardOutput = true;
+            _webServerProcess.StartInfo.RedirectStandardError = true;
+
+            _webServerProcess.OutputDataReceived += (sender, e) =>
+            {
+                Console.WriteLine(e.Data);
+                if (e.Data != null &&
+                    taskWrapper.Task.Status != TaskStatus.RanToCompletion &&
+                    //Though this is not bulletproof for the purpose of local testing
+                    //We assume that if the address is already in use is because we have another
+                    //process hosting the site
+                    (e.Data.Contains("Now listening on") || e.Data.Contains("ADDRINUSE")))
+                {
+                    taskWrapper.SetResult(true);
+                }
+            };
+
+            _webServerProcess.Exited += (sender, e) =>
+            {
+                taskWrapper.SetException(new Exception("Unable to start web server"));
+            };
+
+            Timer timer = null;
+            //We have to declare timer before initializing it because if we don't do this 
+            //we can't dispose it in the action created in the constructor
+            timer = new Timer((state) =>
+            {
+                if (taskWrapper.Task.Status != TaskStatus.RanToCompletion)
+                {
+                    taskWrapper.SetException(
+                        new Exception($"Timed out after {timeout} ms while trying to connect to WebServer! "));
+                }
+                timer.Dispose();
+            }, null, timeout, 0);
+
+            _webServerProcess.Start();
+            _webServerProcess.BeginOutputReadLine();
+
+            await taskWrapper.Task;
+        }
+
+    }
+}