feat(program): add RunWithResult for capturing driver output

src/Playwright/Program.cs

@@ -24,6 +24,7 @@
 
 using System;
 using System.Diagnostics;
+using System.Text;
 using Microsoft.Playwright.Helpers;
 
 namespace Microsoft.Playwright;
@@ -38,43 +39,100 @@ public static int Main(string[] args)
 
     public int Run(string[] args)
     {
-        Func<string?, string> getArgs;
-        string executablePath;
+        Process pwProcess;
         try
         {
-            (executablePath, getArgs) = Driver.GetExecutablePath();
+            pwProcess = CreateDriverProcess(args, captureOutput: false);
         }
         catch
         {
             return PrintError("Microsoft.Playwright assembly was found, but is missing required assets. Please ensure to build your project before running Playwright tool.");
         }
+        using (pwProcess)
+        {
+            pwProcess.Start();
+            pwProcess.WaitForExit();
+            return pwProcess.ExitCode;
+        }
+    }
+
+    /// <summary>
+    /// Runs the Playwright driver with the given arguments and returns the captured stdout, stderr, and exit code.
+    /// Unlike <see cref="Run(string[])"/>, this does not inherit the calling process's stdio, so the output is
+    /// available to callers running under environments (e.g. xUnit) that don't surface inherited console output.
+    /// </summary>
+    /// <param name="args">The arguments to pass to the Playwright driver (e.g. <c>install</c>, <c>codegen</c>).</param>
+    /// <returns>The captured <see cref="RunResult"/>.</returns>
+    public RunResult RunWithResult(string[] args)
+    {
+        using var pwProcess = CreateDriverProcess(args, captureOutput: true);
+
+        var stdout = new StringBuilder();
+        var stderr = new StringBuilder();
+        pwProcess.OutputDataReceived += (_, e) =>
+        {
+            if (e.Data != null)
+            {
+                stdout.AppendLine(e.Data);
+            }
+        };
+        pwProcess.ErrorDataReceived += (_, e) =>
+        {
+            if (e.Data != null)
+            {
+                stderr.AppendLine(e.Data);
+            }
+        };
+
+        pwProcess.Start();
+        pwProcess.BeginOutputReadLine();
+        pwProcess.BeginErrorReadLine();
+        pwProcess.WaitForExit();
+
+        return new RunResult(pwProcess.ExitCode, stdout.ToString(), stderr.ToString());
+    }
 
-        var playwrightStartInfo = new ProcessStartInfo(executablePath, getArgs(args.Length > 0 ? "\"" + string.Join("\" \"", args) + "\"" : null))
+    private static Process CreateDriverProcess(string[] args, bool captureOutput)
+    {
+        var (executablePath, getArgs) = Driver.GetExecutablePath();
+        var startInfo = new ProcessStartInfo(executablePath, getArgs(args.Length > 0 ? "\"" + string.Join("\" \"", args) + "\"" : null))
         {
             UseShellExecute = false,
             // This works after net8.0-preview-4
             // https://github.com/dotnet/runtime/pull/82662
             WindowStyle = ProcessWindowStyle.Hidden,
+            RedirectStandardOutput = captureOutput,
+            RedirectStandardError = captureOutput,
         };
         foreach (var pair in Driver.EnvironmentVariables)
         {
-            playwrightStartInfo.EnvironmentVariables[pair.Key] = pair.Value;
+            startInfo.EnvironmentVariables[pair.Key] = pair.Value;
         }
-
-        using var pwProcess = new Process()
-        {
-            StartInfo = playwrightStartInfo,
-        };
-
-        pwProcess.Start();
-
-        pwProcess.WaitForExit();
-        return pwProcess.ExitCode;
+        return new Process() { StartInfo = startInfo };
     }
 
     private static int PrintError(string error)
     {
         Console.Error.WriteLine("\x1b[91m" + error + "\x1b[0m");
         return 1;
     }
+
+    /// <summary>
+    /// Captured result of <see cref="RunWithResult(string[])"/>.
+    /// </summary>
+    public class RunResult
+    {
+        internal RunResult(int exitCode, string standardOutput, string standardError)
+        {
+            ExitCode = exitCode;
+            StandardOutput = standardOutput;
+            StandardError = standardError;
+        }
+
+        public int ExitCode { get; }
+
+        public string StandardOutput { get; }
+
+        public string StandardError { get; }
+    }
 }