assertThrows(IOException.class, () -> new TestCharSource(STRING).copyTo(failSink));
    assertTrue(failSink.wasStreamClosed());
  }

  public void testClosesOnErrors_whenWritingFromReaderThatThrows() {
    TestCharSink okSink = new TestCharSink();
    assertThrows(IOException.class, () -> okSink.writeFrom(new TestReader(READ_THROWS)));
    assertTrue(okSink.wasStreamClosed());
  }