diff --git a/core/kotlinx-coroutines-core/src/test/kotlin/guide/example-context-04.kt b/core/kotlinx-coroutines-core/src/test/kotlin/guide/example-context-04.kt
index 228b4fc..43caf8b 100644
--- a/core/kotlinx-coroutines-core/src/test/kotlin/guide/example-context-04.kt
+++ b/core/kotlinx-coroutines-core/src/test/kotlin/guide/example-context-04.kt
@@ -22,13 +22,15 @@
 fun log(msg: String) = println("[${Thread.currentThread().name}] $msg")
 
 fun main(args: Array<String>) {
-    val ctx1 = newSingleThreadContext("Ctx1")
-    val ctx2 = newSingleThreadContext("Ctx2")
-    runBlocking(ctx1) {
-        log("Started in ctx1")
-        run(ctx2) {
-            log("Working in ctx2")
+    newSingleThreadContext("Ctx1").use { ctx1 ->
+        newSingleThreadContext("Ctx2").use { ctx2 ->
+            runBlocking(ctx1) {
+                log("Started in ctx1")
+                run(ctx2) {
+                    log("Working in ctx2")
+                }
+                log("Back to ctx1")
+            }
         }
-        log("Back to ctx1")
     }
 }
diff --git a/core/kotlinx-coroutines-core/src/test/kotlin/kotlinx/coroutines/experimental/ExecutorsTest.kt b/core/kotlinx-coroutines-core/src/test/kotlin/kotlinx/coroutines/experimental/ExecutorsTest.kt
index 71b3f35..0ae885d 100644
--- a/core/kotlinx-coroutines-core/src/test/kotlin/kotlinx/coroutines/experimental/ExecutorsTest.kt
+++ b/core/kotlinx-coroutines-core/src/test/kotlin/kotlinx/coroutines/experimental/ExecutorsTest.kt
@@ -31,7 +31,7 @@
         runBlocking(context) {
             checkThreadName("TestThread")
         }
-        context[Job]!!.cancel()
+        context.close()
     }
 
     @Test
@@ -40,7 +40,7 @@
         runBlocking(context) {
             checkThreadName("TestPool")
         }
-        context[Job]!!.cancel()
+        context.close()
     }
 
     @Test
@@ -63,7 +63,7 @@
             }
             checkThreadName("Ctx1")
         }
-        ctx1[Job]!!.cancel()
-        ctx2[Job]!!.cancel()
+        ctx1.close()
+        ctx2.close()
     }
 }
\ No newline at end of file
diff --git a/core/kotlinx-coroutines-core/src/test/kotlin/kotlinx/coroutines/experimental/channels/BroadcastChannelMultiReceiveStressTest.kt b/core/kotlinx-coroutines-core/src/test/kotlin/kotlinx/coroutines/experimental/channels/BroadcastChannelMultiReceiveStressTest.kt
index 8b087ca..220afbe 100644
--- a/core/kotlinx-coroutines-core/src/test/kotlin/kotlinx/coroutines/experimental/channels/BroadcastChannelMultiReceiveStressTest.kt
+++ b/core/kotlinx-coroutines-core/src/test/kotlin/kotlinx/coroutines/experimental/channels/BroadcastChannelMultiReceiveStressTest.kt
@@ -52,7 +52,7 @@
 
     @After
     fun tearDown() {
-        pool.cancel()
+        pool.close()
     }
 
     @Test
diff --git a/core/kotlinx-coroutines-core/src/test/kotlin/kotlinx/coroutines/experimental/channels/ConflatedChannelCloseStressTest.kt b/core/kotlinx-coroutines-core/src/test/kotlin/kotlinx/coroutines/experimental/channels/ConflatedChannelCloseStressTest.kt
index 0025df7..fbc55bc 100644
--- a/core/kotlinx-coroutines-core/src/test/kotlin/kotlinx/coroutines/experimental/channels/ConflatedChannelCloseStressTest.kt
+++ b/core/kotlinx-coroutines-core/src/test/kotlin/kotlinx/coroutines/experimental/channels/ConflatedChannelCloseStressTest.kt
@@ -35,7 +35,9 @@
     val pool = newFixedThreadPoolContext(nSenders + 2, "TestStressClose")
 
     @After
-    fun tearDown() { pool[Job]!!.cancel() }
+    fun tearDown() {
+        pool.close()
+    }
 
     @Test
     fun testStressClose() = runBlocking<Unit> {