Fix toString representation of JobListenableFuture

Also add tests for toString.

Author: vadimsemenov

integration/kotlinx-coroutines-guava/src/ListenableFuture.kt

@@ -455,7 +455,7 @@ private class JobListenableFuture<T>(private val jobToCancel: Job): ListenableFu
             try {
                 when (val result = Uninterruptibles.getUninterruptibly(auxFuture)) {
                     is Cancelled -> append("CANCELLED, cause=[${result.exception}]")
-                    else -> append("SUCCESS, result=[$result")
+                    else -> append("SUCCESS, result=[$result]")
                 }
             } catch (e: CancellationException) {
                 // `this` future was cancelled by `Future.cancel`. In this case there's no cause or message.
@@ -469,6 +469,7 @@ private class JobListenableFuture<T>(private val jobToCancel: Job): ListenableFu
         } else {
             append("PENDING, delegate=[$auxFuture]")
         }
+        append(']')
     }
 }
 

integration/kotlinx-coroutines-guava/test/ListenableFutureToStringTest.kt

@@ -0,0 +1,69 @@
+/*
+ * Copyright 2016-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+package kotlinx.coroutines.guava
+
+import kotlinx.coroutines.*
+import org.junit.Test
+import kotlin.test.*
+
+class ListenableFutureToStringTest : TestBase() {
+    @Test
+    fun testSuccessfulFuture() = runTest {
+        val deferred = CompletableDeferred("OK")
+        val succeededFuture = deferred.asListenableFuture()
+        val toString = succeededFuture.toString()
+        assertTrue(message = "Unexpected format: $toString") {
+            toString.matches(Regex("""kotlinx\.coroutines\.guava\.JobListenableFuture@[^\[]*\[status=SUCCESS, result=\[OK]]"""))
+        }
+    }
+
+    @Test
+    fun testFailedFuture() = runTest {
+        val exception = TestRuntimeException("test")
+        val deferred = CompletableDeferred<String>().apply {
+            completeExceptionally(exception)
+        }
+        val failedFuture = deferred.asListenableFuture()
+        val toString = failedFuture.toString()
+        assertTrue(message = "Unexpected format: $toString") {
+            toString.matches(Regex("""kotlinx\.coroutines\.guava\.JobListenableFuture@[^\[]*\[status=FAILURE, cause=\[$exception]]"""))
+        }
+    }
+
+    @Test
+    fun testPendingFuture() = runTest {
+        val deferred = CompletableDeferred<String>()
+        val pendingFuture = deferred.asListenableFuture()
+        val toString = pendingFuture.toString()
+        assertTrue(message = "Unexpected format: $toString") {
+            toString.matches(Regex("""kotlinx\.coroutines\.guava\.JobListenableFuture@[^\[]*\[status=PENDING, delegate=\[.*]]"""))
+        }
+    }
+
+    @Test
+    fun testCancelledCoroutineAsListenableFuture() = runTest {
+        val exception = CancellationException("test")
+        val deferred = CompletableDeferred<String>().apply {
+            cancel(exception)
+        }
+        val cancelledFuture = deferred.asListenableFuture()
+        val toString = cancelledFuture.toString()
+        assertTrue(message = "Unexpected format: $toString") {
+            toString.matches(Regex("""kotlinx\.coroutines\.guava\.JobListenableFuture@[^\[]*\[status=CANCELLED, cause=\[$exception]]"""))
+        }
+    }
+
+    @Test
+    fun testCancelledFuture() = runTest {
+        val deferred = CompletableDeferred<String>()
+        val cancelledFuture = deferred.asListenableFuture().apply {
+            cancel(false)
+        }
+        val toString = cancelledFuture.toString()
+        assertTrue(message = "Unexpected format: $toString") {
+            toString.matches(Regex("""kotlinx\.coroutines\.guava\.JobListenableFuture@[^\[]*\[status=CANCELLED]"""))
+        }
+    }
+}