#2 Add unit test and fix for potential bug dotnet/aspnetcore#6146

Author: EEParker

VueCliMiddleware.Tests/EventedStreamReaderTests.cs

@@ -0,0 +1,34 @@
+using System.IO;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace VueCliMiddleware.Tests
+{
+    [TestClass]
+    public class EventedStreamReaderTests
+    {
+        [TestMethod]
+        public async Task ReadChunks_MultipleNewLines_OnCompleteLineFiresEachNewline()
+        {
+
+            string testMessage = "this \nis \na \ntest \nof \nmultiple \nnewlines\n  trailing data";
+            int numNewLines = testMessage.Split('\n').Length - 1;
+            int chunksReceived = 0;
+            int linesReceived = 0;
+
+            using (var ms = new MemoryStream(Encoding.UTF8.GetBytes(testMessage)))
+            {
+                var streamReader = new StreamReader(ms);
+
+                var esr = new EventedStreamReader(streamReader);
+                esr.OnReceivedChunk += (e) => Interlocked.Increment(ref chunksReceived);
+                esr.OnReceivedLine += (e) => Interlocked.Increment(ref linesReceived);
+                await Task.Delay(200);
+            }
+
+            Assert.AreEqual(numNewLines, linesReceived);
+        }
+    }
+}

VueCliMiddleware.Tests/VueCliMiddleware.Tests.csproj

@@ -0,0 +1,21 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netcoreapp2.2</TargetFramework>
+
+    <IsPackable>false</IsPackable>
+
+    <RootNamespace>VueCliMiddleware</RootNamespace>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.9.0" />
+    <PackageReference Include="MSTest.TestAdapter" Version="1.4.0" />
+    <PackageReference Include="MSTest.TestFramework" Version="1.4.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\src\VueCliMiddleware.csproj" />
+  </ItemGroup>
+
+</Project>

src/Util/Internals.cs

@@ -14,6 +14,8 @@
 using System.Text;
 using System.Text.RegularExpressions;
 
+
+[assembly: System.Runtime.CompilerServices.InternalsVisibleTo("VueCliMiddleware.Tests")]
 namespace VueCliMiddleware
 {
     internal static class LoggerFinder
@@ -154,17 +156,23 @@ private async Task Run()
 
                 OnChunk(new ArraySegment<char>(buf, 0, chunkLength));
 
-                var lineBreakPos = Array.IndexOf(buf, '\n', 0, chunkLength);
-                if (lineBreakPos < 0)
-                {
-                    _linesBuffer.Append(buf, 0, chunkLength);
-                }
-                else
+                int lineBreakPos = -1;
+                int startPos = 0;
+
+                // get all the newlines
+                while ((lineBreakPos = Array.IndexOf(buf, '\n', startPos, chunkLength - startPos)) >= 0 && startPos < chunkLength)
                 {
-                    _linesBuffer.Append(buf, 0, lineBreakPos + 1);
+                    var length = (lineBreakPos + 1) - startPos;
+                    _linesBuffer.Append(buf, startPos, length);
                     OnCompleteLine(_linesBuffer.ToString());
                     _linesBuffer.Clear();
-                    _linesBuffer.Append(buf, lineBreakPos + 1, chunkLength - (lineBreakPos + 1));
+                    startPos = lineBreakPos + 1;
+                }
+
+                // get the rest
+                if (lineBreakPos < 0 && startPos < chunkLength)
+                {
+                    _linesBuffer.Append(buf, startPos, chunkLength);
                 }
             }
         }

src/VueCliMiddleware.sln

@@ -5,6 +5,8 @@ VisualStudioVersion = 15.0.28010.2026
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "VueCliMiddleware", "VueCliMiddleware.csproj", "{6EF79200-935A-4EBB-BB10-EB233A360210}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "VueCliMiddleware.Tests", "..\VueCliMiddleware.Tests\VueCliMiddleware.Tests.csproj", "{36DA789C-1C87-48A3-9A9E-804E9BA5C141}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -15,6 +17,10 @@ Global
 		{6EF79200-935A-4EBB-BB10-EB233A360210}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{6EF79200-935A-4EBB-BB10-EB233A360210}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{6EF79200-935A-4EBB-BB10-EB233A360210}.Release|Any CPU.Build.0 = Release|Any CPU
+		{36DA789C-1C87-48A3-9A9E-804E9BA5C141}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{36DA789C-1C87-48A3-9A9E-804E9BA5C141}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{36DA789C-1C87-48A3-9A9E-804E9BA5C141}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{36DA789C-1C87-48A3-9A9E-804E9BA5C141}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE