assertEquals(
            "request body is required",
            assertThrows(
                ElasticsearchParseException.class,
                () -> new RestBulkAction(
                    Settings.EMPTY,
                    ClusterSettings.createBuiltInClusterSettings(),
                    new IncrementalBulkService(mock(Client.class), mock(IndexingPressure.class), MeterRegistry.NOOP)
                ).handleRequest(
                    new FakeRestRequest.Builder(xContentRegistry()).withPath("my_index/_bulk")
                        .withContentLength(0)
                        .withBody(new FakeHttpBodyStream())
                        .build(),
                    mock(RestChannel.class),
                    mock(NodeClient.class)
                )
            ).getMessage()
        );