Fixed delay in arbitrary contexts

Fixes #133

Author: elizarov

core/kotlinx-coroutines-core/src/main/kotlin/kotlinx/coroutines/experimental/CancellableContinuation.kt

@@ -249,13 +249,13 @@ internal class CancellableContinuationImpl<in T>(
     }
 
     override fun CoroutineDispatcher.resumeUndispatched(value: T) {
-        val dc = delegate as? DispatchedContinuation ?: throw IllegalArgumentException("Must be used with DispatchedContinuation")
-        resumeImpl(value, if (dc.dispatcher === this) MODE_UNDISPATCHED else resumeMode)
+        val dc = delegate as? DispatchedContinuation
+        resumeImpl(value, if (dc?.dispatcher === this) MODE_UNDISPATCHED else resumeMode)
     }
 
     override fun CoroutineDispatcher.resumeUndispatchedWithException(exception: Throwable) {
-        val dc = delegate as? DispatchedContinuation ?: throw IllegalArgumentException("Must be used with DispatchedContinuation")
-        resumeWithExceptionImpl(exception, if (dc.dispatcher === this) MODE_UNDISPATCHED else resumeMode)
+        val dc = delegate as? DispatchedContinuation
+        resumeWithExceptionImpl(exception, if (dc?.dispatcher === this) MODE_UNDISPATCHED else resumeMode)
     }
 
     override fun nameString(): String =

core/kotlinx-coroutines-core/src/test/kotlin/kotlinx/coroutines/experimental/DelayTest.kt

@@ -0,0 +1,79 @@
+/*
+ * Copyright 2016-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package kotlinx.coroutines.experimental
+
+import org.hamcrest.MatcherAssert.assertThat
+import org.hamcrest.core.IsEqual
+import org.junit.Test
+import java.util.concurrent.Executor
+import java.util.concurrent.Executors
+import kotlin.coroutines.experimental.AbstractCoroutineContextElement
+import kotlin.coroutines.experimental.Continuation
+import kotlin.coroutines.experimental.ContinuationInterceptor
+import kotlin.coroutines.experimental.CoroutineContext
+
+class DelayTest : TestBase() {
+    /**
+     * Test that delay works properly in contexts with custom [ContinuationInterceptor]
+     */
+    @Test
+    fun testDelayInArbitraryContext() = runBlocking {
+        var thread: Thread? = null
+        val pool = Executors.newFixedThreadPool(1) { runnable ->
+            Thread(runnable).also { thread = it }
+        }
+        val context = CustomInterceptor(pool)
+        val c = async(context) {
+            assertThat(Thread.currentThread(), IsEqual(thread))
+            delay(100)
+            assertThat(Thread.currentThread(), IsEqual(thread))
+            42
+        }
+        assertThat(c.await(), IsEqual(42))
+        pool.shutdown()
+    }
+
+
+    @Test
+    fun testDelayWithoutDispatcher() = runBlocking(CoroutineName("testNoDispatcher.main")) {
+        // launch w/o a specified dispatcher
+        val c = async(CoroutineName("testNoDispatcher.inner")) {
+            delay(100)
+            42
+        }
+        assertThat(c.await(), IsEqual(42))
+    }
+
+    class CustomInterceptor(val pool: Executor) : AbstractCoroutineContextElement(ContinuationInterceptor), ContinuationInterceptor {
+        override fun <T> interceptContinuation(continuation: Continuation<T>): Continuation<T> =
+            Wrapper(pool, continuation)
+    }
+
+    class Wrapper<T>(val pool: Executor, val cont: Continuation<T>) : Continuation<T> {
+        override val context: CoroutineContext
+            get() = cont.context
+
+        override fun resume(value: T) {
+            pool.execute { cont.resume(value) }
+        }
+
+        override fun resumeWithException(exception: Throwable) {
+            pool.execute { cont.resumeWithException(exception) }
+        }
+    }
+
+}