abstractFuture.set(DATA1);
    ExecutorSpy spy = new ExecutorSpy(directExecutor());
    ListenableFuture<String> listenableFuture = listenInPoolThread(abstractFuture, spy);

    SingleCallListener singleCallListener = new SingleCallListener();
    singleCallListener.expectCall();

    assertFalse(spy.wasExecuted);
    assertFalse(singleCallListener.wasCalled());

    SpyAppendable spy = new SpyAppendable();
    Writer writer = new AppendableWriter(spy);

    writer.write("Hello");
    assertFalse(spy.flushed);
    assertFalse(spy.closed);

    writer.flush();
    assertTrue(spy.flushed);
    assertFalse(spy.closed);

    writer.close();
    assertTrue(spy.flushed);
    assertTrue(spy.closed);
  }

import org.checkerframework.checker.nullness.qual.Nullable;

/** Implementation of {@link Futures#immediateFuture}. */
@GwtCompatible
@ElementTypesAreNonnullByDefault
// TODO(cpovirk): Make this final (but that may break Mockito spy calls).
class ImmediateFuture<V extends @Nullable Object> implements ListenableFuture<V> {
  static final ListenableFuture<?> NULL = new ImmediateFuture<@Nullable Object>(null);

    abstractFuture.set(DATA1);
    ExecutorSpy spy = new ExecutorSpy(directExecutor());
    ListenableFuture<String> listenableFuture = listenInPoolThread(abstractFuture, spy);

    SingleCallListener singleCallListener = new SingleCallListener();
    singleCallListener.expectCall();

    assertFalse(spy.wasExecuted);
    assertFalse(singleCallListener.wasCalled());

    SpyAppendable spy = new SpyAppendable();
    Writer writer = new AppendableWriter(spy);

    writer.write("Hello");
    assertFalse(spy.flushed);
    assertFalse(spy.closed);

    writer.flush();
    assertTrue(spy.flushed);
    assertFalse(spy.closed);

    writer.close();
    assertTrue(spy.flushed);
    assertTrue(spy.closed);
  }

    FunctionSpy<Object, String> spy = new FunctionSpy<>(constant("bar"));
    Future<String> input = immediateFuture("foo");
    Future<String> transformed = lazyTransform(input, spy);
    spy.verifyCallCount(0);
    assertEquals("bar", getDone(transformed));
    spy.verifyCallCount(1);
    assertEquals("bar", getDone(transformed));
    spy.verifyCallCount(2);
  }

  @J2ktIncompatible

    FunctionSpy<Object, String> spy = new FunctionSpy<>(constant("bar"));
    Future<String> input = immediateFuture("foo");
    Future<String> transformed = lazyTransform(input, spy);
    spy.verifyCallCount(0);
    assertEquals("bar", getDone(transformed));
    spy.verifyCallCount(1);
    assertEquals("bar", getDone(transformed));
    spy.verifyCallCount(2);
  }

  @J2ktIncompatible