1 files changed, 187 insertions, 0 deletions
diff --git a/guava-tests/test/com/google/common/util/concurrent/FuturesTransformAsyncFunctionTest.java b/guava-tests/test/com/google/common/util/concurrent/FuturesTransformAsyncFunctionTest.java
new file mode 100644
index 000000000..4b51bed36
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+++ b/guava-tests/test/com/google/common/util/concurrent/FuturesTransformAsyncFunctionTest.java
@@ -0,0 +1,187 @@
+/*
+ * Copyright (C) 2008 The Guava Authors
+ *
+ * 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 com.google.common.util.concurrent;
+
+import static com.google.common.util.concurrent.Uninterruptibles.awaitUninterruptibly;
+
+import com.google.common.util.concurrent.ForwardingListenableFuture.SimpleForwardingListenableFuture;
+
+import java.lang.reflect.UndeclaredThrowableException;
+import java.util.concurrent.CancellationException;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutionException;
+
+/**
+ * Unit tests for {@link Futures#transform(ListenableFuture, AsyncFunction)}.
+ *
+ * @author Nishant Thakkar
+ */
+public class FuturesTransformAsyncFunctionTest
+    extends AbstractChainedListenableFutureTest<String> {
+  protected static final int SLOW_OUTPUT_VALID_INPUT_DATA = 2;
+  protected static final int SLOW_FUNC_VALID_INPUT_DATA = 3;
+  private static final String RESULT_DATA = "SUCCESS";
+
+  private SettableFuture<String> outputFuture;
+  // Signals that the function is waiting to complete
+  private CountDownLatch funcIsWaitingLatch;
+  // Signals the function so it will complete
+  private CountDownLatch funcCompletionLatch;
+
+  @Override protected ListenableFuture<String> buildChainingFuture(
+      ListenableFuture<Integer> inputFuture) {
+    outputFuture = SettableFuture.create();
+    funcIsWaitingLatch = new CountDownLatch(1);
+    funcCompletionLatch = new CountDownLatch(1);
+    return Futures.transform(inputFuture, new ChainingFunction());
+  }
+
+  @Override protected String getSuccessfulResult() {
+    return RESULT_DATA;
+  }
+
+  private class ChainingFunction implements AsyncFunction<Integer, String> {
+    @Override
+    public ListenableFuture<String> apply(Integer input) {
+      switch (input) {
+        case VALID_INPUT_DATA: outputFuture.set(RESULT_DATA); break;
+        case SLOW_OUTPUT_VALID_INPUT_DATA: break;  // do nothing to the result
+        case SLOW_FUNC_VALID_INPUT_DATA:
+          funcIsWaitingLatch.countDown();
+          awaitUninterruptibly(funcCompletionLatch);
+          break;
+        default: throw new UndeclaredThrowableException(EXCEPTION);
+      }
+      return outputFuture;
+    }
+  }
+
+  public void testFutureGetThrowsFunctionException() throws Exception {
+    inputFuture.set(EXCEPTION_DATA);
+    listener.assertException(EXCEPTION);
+  }
+
+  public void testFutureGetThrowsCancellationIfInputCancelled()
+      throws Exception {
+    inputFuture.cancel(true); // argument is ignored
+    try {
+      resultFuture.get();
+      fail("Result future must throw CancellationException"
+          + " if input future is cancelled.");
+    } catch (CancellationException expected) {}
+  }
+
+  public void testFutureGetThrowsCancellationIfOutputCancelled()
+      throws Exception {
+    inputFuture.set(SLOW_OUTPUT_VALID_INPUT_DATA);
+    outputFuture.cancel(true); // argument is ignored
+    try {
+      resultFuture.get();
+      fail("Result future must throw CancellationException"
+          + " if function output future is cancelled.");
+    } catch (CancellationException expected) {}
+  }
+
+  public void testFutureCancelBeforeInputCompletion() throws Exception {
+    assertTrue(resultFuture.cancel(true));
+    assertTrue(resultFuture.isCancelled());
+    assertTrue(inputFuture.isCancelled());
+    assertFalse(outputFuture.isCancelled());
+    try {
+      resultFuture.get();
+      fail("Result future is cancelled and should have thrown a"
+          + " CancellationException");
+    } catch (CancellationException expected) {}
+  }
+
+  public void testFutureCancellableBeforeOutputCompletion() throws Exception {
+    inputFuture.set(SLOW_OUTPUT_VALID_INPUT_DATA);
+    assertTrue(resultFuture.cancel(true));
+    assertTrue(resultFuture.isCancelled());
+    assertFalse(inputFuture.isCancelled());
+    assertTrue(outputFuture.isCancelled());
+    try {
+      resultFuture.get();
+      fail("Result future is cancelled and should have thrown a"
+          + " CancellationException");
+    } catch (CancellationException expected) {}
+  }
+
+  public void testFutureCancellableBeforeFunctionCompletion() throws Exception {
+    // Set the result in a separate thread since this test runs the function
+    // (which will block) in the same thread.
+    new Thread() {
+      @Override
+      public void run() {
+        inputFuture.set(SLOW_FUNC_VALID_INPUT_DATA);
+      }
+    }.start();
+    funcIsWaitingLatch.await();
+
+    assertTrue(resultFuture.cancel(true));
+    assertTrue(resultFuture.isCancelled());
+    assertFalse(inputFuture.isCancelled());
+    assertFalse(outputFuture.isCancelled());
+    try {
+      resultFuture.get();
+      fail("Result future is cancelled and should have thrown a"
+          + " CancellationException");
+    } catch (CancellationException expected) {}
+
+    funcCompletionLatch.countDown();  // allow the function to complete
+    try {
+      outputFuture.get();
+      fail("The function output future is cancelled and should have thrown a"
+          + " CancellationException");
+    } catch (CancellationException expected) {}
+  }
+
+  public void testFutureCancelAfterCompletion() throws Exception {
+    inputFuture.set(VALID_INPUT_DATA);
+    assertFalse(resultFuture.cancel(true));
+    assertFalse(resultFuture.isCancelled());
+    assertFalse(inputFuture.isCancelled());
+    assertFalse(outputFuture.isCancelled());
+    assertEquals(RESULT_DATA, resultFuture.get());
+  }
+
+  public void testFutureGetThrowsRuntimeException() throws Exception {
+    BadFuture badInput = new BadFuture(Futures.immediateFuture(20));
+    ListenableFuture<String> chain = buildChainingFuture(badInput);
+    try {
+      chain.get();
+      fail("Future.get must throw an exception when the input future fails.");
+    } catch (ExecutionException e) {
+      assertSame(RuntimeException.class, e.getCause().getClass());
+    }
+  }
+
+  /**
+   * Proxy to throw a {@link RuntimeException} out of the {@link #get()} method.
+   */
+  public static class BadFuture
+      extends SimpleForwardingListenableFuture<Integer> {
+    protected BadFuture(ListenableFuture<Integer> delegate) {
+      super(delegate);
+    }
+
+    @Override
+    public Integer get() {
+      throw new RuntimeException("Oops");
+    }
+  }
+}