Fix AsyncStreamReader sending extra string and tests

StabilityMatrix.Core/Processes/AsyncStreamReader.cs

@@ -254,6 +254,9 @@ internal sealed class AsyncStreamReader : IDisposable
                     else
                     {
                         // Send buffer up to this point, not including \r
+                        // But skip if there's no content
+                        if (currentIndex == lineStart) break;
+                        
                         var line = _sb.ToString(lineStart, currentIndex - lineStart);
                         lock (_messageQueue)
                         {

StabilityMatrix.Tests/Core/AsyncStreamReaderTests.cs

@@ -13,62 +13,68 @@ public class AsyncStreamReaderTests
     
     [DataTestMethod]
     // Test newlines handling for \r\n, \n
-    [DataRow("a\r\nb\nc", "a\r\n", "b\n", "c")]
+    [DataRow("a\r\nb\nc", "a\r\n", "b\n", "c", null)]
     // Carriage returns \r should be sent as is
-    [DataRow("a\rb\rc", "a", "\rb", "\rc")]
-    [DataRow("a1\ra2\nb1\rb2", "a1", "\ra2\n", "b1", "\rb2")]
+    [DataRow("a\rb\rc", "a", "\rb", "\rc", null)]
+    [DataRow("a1\ra2\nb1\rb2", "a1", "\ra2\n", "b1", "\rb2", null)]
     // Ansi escapes should be seperated
-    [DataRow("\x1b[A\x1b[A", "\x1b[A", "\x1b[A")]
+    [DataRow("\x1b[A\x1b[A", "\x1b[A", "\x1b[A", null)]
     // Mixed Ansi and newlines
-    [DataRow("a \x1b[A\r\n\r xyz", "a ", "\x1b[A", "\r\n", "\r xyz")]
-    public async Task TestRead(string source, params string[] expected)
+    [DataRow("a \x1b[A\r\n\r xyz", "a ", "\x1b[A", "\r\n", "\r xyz", null)]
+    public async Task TestRead(string source, params string?[] expected)
     {
-        var queue = new Queue<string?>(expected);
+        var results = new List<string?>();
         
         var callback = new Action<string?>(s =>
         {
-            Assert.IsTrue(queue.Count > 0);
-            Assert.AreEqual(queue.Dequeue(), s);
+            results.Add(s);
         });
         
-        var stream = new MemoryStream(Encoding.UTF8.GetBytes(source));
-        
-        // Make the reader
-        using var reader = new AsyncStreamReader(stream, callback, Encoding.UTF8);
-        
-        // Begin read line and wait until finish
-        reader.BeginReadLine();
-        await reader.EOF;
+        using var stream = new MemoryStream(Encoding.UTF8.GetBytes(source));
+        using (var reader = new AsyncStreamReader(stream, callback, Encoding.UTF8))
+        {
+            // Begin read line and wait until finish
+            reader.BeginReadLine();
+            // Wait for maximum 1 second
+            await reader.EOF.WaitAsync(new CancellationTokenSource(1000).Token);
+        }
 
-        // Check if all expected strings were read
-        Assert.AreEqual(0, queue.Count, "Remaining: " + string.Join(", ", queue.ToArray()
-            .Select(s => (s ?? "<null>").ToRepr())));
+        // Check expected output matches
+        Assert.IsTrue(expected.SequenceEqual(results.ToArray()), 
+            "Results [{0}] do not match expected [{1}]", 
+            string.Join(", ", results.Select(s => s?.ToRepr() ?? "<null>")), 
+            string.Join(", ", expected.Select(s => s?.ToRepr() ?? "<null>")));
     }
     
     [TestMethod]
     public async Task TestCarriageReturnHandling()
     {
-        // The previous buffer should be sent when \r is encountered
-        const string source = "dog\r\ncat\r123\r456";
-        var stream = new MemoryStream(Encoding.UTF8.GetBytes(source));
+        var expected = new[] {"dog\r\n", "cat", "\r123", "\r456", null};
         
-        var queue = new Queue<string?>(new[] {"dog\r\n", "cat", "\r123", "\r456"});
+        var results = new List<string?>();
         
         var callback = new Action<string?>(s =>
         {
-            Assert.IsTrue(queue.Count > 0);
-            Assert.AreEqual(queue.Dequeue(), s);
+            results.Add(s);
         });
         
-        // Make the reader
-        using var reader = new AsyncStreamReader(stream, callback, Encoding.UTF8);
+        // The previous buffer should be sent when \r is encountered
+        const string source = "dog\r\ncat\r123\r456";
         
-        // Begin read line and wait until finish
-        reader.BeginReadLine();
-        await reader.EOF;
+        // Make the reader
+        using var stream = new MemoryStream(Encoding.UTF8.GetBytes(source));
+        using (var reader = new AsyncStreamReader(stream, callback, Encoding.UTF8))
+        {
+            // Begin read line and wait until finish
+            reader.BeginReadLine();
+            // Wait for maximum 1 second
+            await reader.EOF.WaitAsync(new CancellationTokenSource(1000).Token);
+        }
         
         // Check if all expected strings were read
-        Assert.AreEqual(0, queue.Count, "Remaining: " + string.Join(", ", queue.ToArray()
-            .Select(s => (s ?? "<null>").ToRepr())));
+        Assert.IsTrue(expected.SequenceEqual(results.ToArray()), 
+            "Results [{0}] do not match expected [{1}]", 
+            string.Join(", ", results.Select(s => s?.ToRepr() ?? "<null>")), 
+            string.Join(", ", expected.Select(s => s?.ToRepr() ?? "<null>")));
     }
 }