Add tests.

Author: adityamandaleeka

src/Servers/Kestrel/test/FunctionalTests/RequestTests.cs

@@ -399,6 +399,46 @@ await connection.Receive(
         Assert.False(loggedHigherThanDebug);
     }
 
+    [Fact]
+    public async Task IncompleteRequestBodyDoesNotLogAsApplicationError()
+    {
+        var logMessageReceived = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
+
+        // Listen for the expected log message
+        TestSink.MessageLogged += context =>
+        {
+            if (context.LoggerName == "Microsoft.AspNetCore.Server.Kestrel"
+                && context.EventId.Id == 13
+                && context.LogLevel > LogLevel.Debug)
+            {
+                logMessageReceived.SetResult();
+            }
+        };
+
+        await using var server = new TestServer(async context =>
+        {
+            var buffer = new byte[1024];
+
+            // Attempt to read more of the body than will show up.
+            await context.Request.Body.ReadAsync(buffer, 0, buffer.Length);
+        }, new TestServiceContext(LoggerFactory));
+
+        using (var connection = server.CreateConnection())
+        {
+            await connection.Send(
+                "POST / HTTP/1.1",
+                "Host:",
+                "Connection: keep-alive",
+                "Content-Type: application/json",
+                "Content-Length: 100",  // Declare a larger body than will be sent
+                "",
+                "");
+        }
+
+        // Log message should not have appeared.
+        await Assert.ThrowsAsync<TimeoutException>(() => logMessageReceived.Task.TimeoutAfter(TimeSpan.FromSeconds(1)));
+    }
+
     [Fact]
     public async Task ConnectionResetBetweenRequestsIsLoggedAsDebug()
     {

src/Servers/Kestrel/test/InMemory.FunctionalTests/ChunkedRequestTests.cs

@@ -740,6 +740,9 @@ await connection.ReceiveEnd(
                     "",
                     "");
             }
+
+            // The 400 response should have been logged by default at Error level since the connection wasn't closed when the bad request was handled.
+            Assert.Contains(TestSink.Writes, w => w.LoggerName == "Microsoft.AspNetCore.Server.Kestrel" && w.EventId.Id == 13 && w.LogLevel > LogLevel.Debug);
         }
     }