1 * writeIndex.lookup("key") >> null
        1 * readIndex.lookup("key")

        when:
        twoStageIndex.lookup("other")

        then:
        1 * writeIndex.lookup("other") >> Stub(CachedExternalResource)
        0 * readIndex._
    }

    def "clearing delegates to the writable cache"() {
        when:
        twoStageIndex.clear("key")

        then:
        1 * writeIndex.clear("key")

            } else {
                encoder.writeBoolean(false);
            }
            Integer idx = writeIndex.get(container);
            if (idx == null) {
                // new value
                encoder.writeSmallInt(writeIndex.size());
                writeIndex.put(container, writeIndex.size());
                delegate.write(encoder, container);
            } else {

            } catch (FileNotFoundException e) {
                throw new UncheckedIOException(e);
            }
        }

        @Override
        public void close() {
            output.close();
            writeIndex();
        }

        public void onOutput(long classId, TestOutputEvent outputEvent) {
            onOutput(classId, 0, outputEvent);
        }