Add support for parallel exectution to MarkdownFormatterOutputWriter

README.md

@@ -170,7 +170,7 @@ using NUnit.Framework;
 [SetUpFixture]
 public class AllTestsSetup
 {
-    private readonly MarkdownFormatterOutputWriter _reportWriter = new MarkdownFormatterOutputWriter(title: "Sample tests with NScenario");
+    private readonly MarkdownFormatterOutputWriter _reportWriter = new (title: "Sample tests with NScenario", currentTestIdentifierAccessor: ()=> TestContext.CurrentContext.Test.ID);
 
     [OneTimeSetUp]
     public void GlobalSetup()
@@ -199,7 +199,7 @@ public class AllTestsSetup
 
 ## Test scenario title
 
-Test scenario title is generated by removing underscores and splitting camel/pascalcase string from the test method name (`[CallerMemberName]` is used to retrieve that name). This allows for immediate review of the test name (I saw many, extremely long and totally ridiculous test method names. A good test method name should reveal the intention of the test case, not its details). You can alwasy override the default title by setting it explicitly during test scenario creation (especially useful for parametrized test methods):
+Test scenario title is generated by removing underscores and splitting camel/pascalcase string from the test method name (`[CallerMemberName]` is used to retrieve that name). This allows for immediate review of the test name (I saw many, extremely long and totally ridiculous test method names. A good test method name should reveal the intention of the test case, not its details). You can always override the default title by setting it explicitly during test scenario creation (especially useful for parametrized test methods):
 
 ```cs
 [TestCase(false)]

src/NScenario/NScenario.csproj

@@ -11,6 +11,9 @@
     <PackageLicenseExpression>MIT</PackageLicenseExpression>
     <PackageIcon>logo.jpg</PackageIcon>
     <LangVersion>8</LangVersion>
+    <GenerateDocumentationFile>true</GenerateDocumentationFile>
+    <NoWarn>1591</NoWarn>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
   <ItemGroup>
     <PackageReference Include="MarkdownSharp" Version="2.0.5" />

src/NScenario/OutputWriters/MarkdownFormatterOutputWriter.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Text;
 using MarkdownSharp;
@@ -8,13 +9,34 @@ namespace NScenario.OutputWriters
 {
     public class MarkdownFormatterOutputWriter: IScenarioOutputWriter
     {
-        private readonly StringBuilder _outputBuilder = new StringBuilder();
+        private readonly Func<string> _currentTestIdentifierAccessor;
+        private readonly Dictionary<string, StringBuilder> _outputBuilders = new Dictionary<string, StringBuilder>();
 
-        public MarkdownFormatterOutputWriter(string? title = null)
+        private StringBuilder OutputBuilder
         {
+            get
+            {
+                var testId = _currentTestIdentifierAccessor();
+                if (_outputBuilders.TryGetValue(testId, out var builder))
+                {
+                    return builder;
+                }
+
+                return _outputBuilders[testId] = new StringBuilder();
+            }
+        }
+
+        /// <summary>
+        ///     Export test scenario transcript to markdown report
+        /// </summary>
+        /// <param name="title">Report title</param>
+        /// <param name="currentTestIdentifierAccessor">Function that returns unique identifier representing currently executed scenario. Should be provided when tests are executed in parallel mode</param>
+        public MarkdownFormatterOutputWriter(string? title = null, Func<string>? currentTestIdentifierAccessor = null)
+        {
+            _currentTestIdentifierAccessor = currentTestIdentifierAccessor ?? (() => "SHARED_ID");
             if (title != null)
             {
-                _outputBuilder.AppendLine($"# {title}");
+                OutputBuilder.AppendLine($"# {title}");
             }
         }
 
@@ -24,27 +46,35 @@ public void WriteStepDescription(string description)
             if (prefixPosition >= 0)
             {
                 var newDescription = description.Insert(prefixPosition, "* ");
-                _outputBuilder.AppendLine(newDescription);
+                OutputBuilder.AppendLine(newDescription);
             }
             else
             {
-                _outputBuilder.AppendLine("* " + description);
+                OutputBuilder.AppendLine("* " + description);
             }
         }
 
         public void WriteScenarioTitle(string scenarioTitle)
         {
-            _outputBuilder.AppendLine($"\r\n## {scenarioTitle}\r\n");
+            OutputBuilder.AppendLine($"\r\n## {scenarioTitle}\r\n");
         }
 
-        public string GetMarkdown() => _outputBuilder.ToString();
+        public string GetMarkdown()
+        {
+            var mergedMarkdown = new StringBuilder();
+            foreach (var builder in _outputBuilders.Values)
+            {
+                mergedMarkdown.Append(builder.ToString());
+            }
+            return mergedMarkdown.ToString();
+        }
 
-        public void Save(string path) =>  File.WriteAllText(path, _outputBuilder.ToString(), Encoding.UTF8);
+        public void Save(string path) =>  File.WriteAllText(path, GetMarkdown(), Encoding.UTF8);
 
 
         public void ExportToHtml(string path)
         {
-            var markdownContent = _outputBuilder.ToString();
+            var markdownContent = GetMarkdown();
             var mm = new Markdown();
             var htmlContent = mm.Transform(markdownContent);
             File.WriteAllText(path, $"<html><head></head><body>{htmlContent}<body></html>", Encoding.UTF8);