From 37c33b75aa6e9296cf4bd78ff6d408bd6f482fff Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20=C5=BBarnowski?= <mzarnowski@virtuslab.com>
Date: Wed, 4 Dec 2019 10:43:12 +0100
Subject: [PATCH] Don't wait for output prefix if it is already present

---
 .../metals/debug/DebuggeeOutput.scala         | 24 ++++++++++++-------
 .../internal/metals/debug/TestDebugger.scala  |  5 ++--
 2 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/tests/unit/src/main/scala/scala/meta/internal/metals/debug/DebuggeeOutput.scala b/tests/unit/src/main/scala/scala/meta/internal/metals/debug/DebuggeeOutput.scala
index 2273ca936ea..b7abe25ae04 100644
--- a/tests/unit/src/main/scala/scala/meta/internal/metals/debug/DebuggeeOutput.scala
+++ b/tests/unit/src/main/scala/scala/meta/internal/metals/debug/DebuggeeOutput.scala
@@ -3,13 +3,13 @@ package scala.meta.internal.metals.debug
 import scala.collection.mutable
 import scala.concurrent.Future
 import scala.concurrent.Promise
-import scala.meta.internal.metals.debug.DebuggeeOutput.OutputListener
+import scala.meta.internal.metals.debug.DebuggeeOutput.PrefixPattern
 
 final class DebuggeeOutput {
   private val output = new StringBuilder
-  @volatile private var listeners = mutable.Buffer.empty[OutputListener]
+  @volatile private var listeners = mutable.Buffer.empty[PrefixPattern]
 
-  def apply(): String = output.toString()
+  def apply(): String = synchronized(output.toString())
 
   def append(message: String): Unit = synchronized {
     output.append(message)
@@ -18,15 +18,19 @@ final class DebuggeeOutput {
     listeners = remaining
   }
 
-  def awaitPrefix(category: String, prefix: String): Future[Unit] = {
-    val promise = Promise[Unit]()
-    listeners.append(new OutputListener(prefix, promise))
-    promise.future
+  def awaitPrefix(prefix: String): Future[Unit] = synchronized {
+    if (output.startsWith(prefix)) {
+      Future.unit
+    } else {
+      val promise = Promise[Unit]()
+      listeners.append(new PrefixPattern(prefix, promise))
+      promise.future
+    }
   }
 }
 
 object DebuggeeOutput {
-  protected final class OutputListener(prefix: String, promise: Promise[Unit]) {
+  protected final class PrefixPattern(prefix: String, promise: Promise[Unit]) {
     def matches(output: String): Boolean = {
       if (output.startsWith(prefix)) {
         promise.success(())
@@ -35,5 +39,9 @@ object DebuggeeOutput {
         false
       }
     }
+
+    def foo(): Unit = {
+      promise.success(())
+    }
   }
 }
diff --git a/tests/unit/src/main/scala/scala/meta/internal/metals/debug/TestDebugger.scala b/tests/unit/src/main/scala/scala/meta/internal/metals/debug/TestDebugger.scala
index 6ea0f493054..53b021ac344 100644
--- a/tests/unit/src/main/scala/scala/meta/internal/metals/debug/TestDebugger.scala
+++ b/tests/unit/src/main/scala/scala/meta/internal/metals/debug/TestDebugger.scala
@@ -60,11 +60,12 @@ final class TestDebugger(connect: RemoteServer.Listener => Debugger)(
     import org.eclipse.lsp4j.debug.{OutputEventArgumentsCategory => Category}
     ifNotFailed {
       output
-        .awaitPrefix(Category.STDOUT, prefix)
+        .awaitPrefix(prefix)
         .withTimeout(seconds, TimeUnit.SECONDS)
         .recoverWith {
           case timeout: TimeoutException =>
-            val error = s"No prefix [$prefix] in [${output()}]"
+            val error =
+              s"No prefix [${prefix.getBytes()}] in [${output().getBytes()}]"
             Future.failed(new Exception(error, timeout))
         }
     }