### Question:
TabpageStreamApi extends BaseStreamApi implements NeovimTabpageApi { @Override public CompletableFuture<Integer> getNumber() { return sendWithResponseOfType(prepareMessage(GET_NUMBER), Integer.class); } TabpageStreamApi(ReactiveRpcStreamer reactiveRpcStreamer, Tabpage model); @Override Tabpage get(); @Override CompletableFuture<List<NeovimWindowApi>> getWindows(); @Override CompletableFuture<NeovimWindowApi> getWindow(); @Override CompletableFuture<Object> getVar(String name); @Override CompletableFuture<Void> setVar(String name, Object value); @Override CompletableFuture<Void> deleteVar(String name); @Override CompletableFuture<Integer> getNumber(); @Override CompletableFuture<Boolean> isValid(); @Override String toString();  }### Answer:
@Test public void getNumberTest() throws ExecutionException, InterruptedException { assertNormalBehavior( () -> CompletableFuture.completedFuture(new ResponseMessage(1, null, 1)), () -> tabpageStreamApi.getNumber(), request -> assertMethodAndArguments(request, NeovimTabpageApi.GET_NUMBER, tabpage), result -> assertEquals(1, result.intValue()) ); assertErrorBehavior( () -> tabpageStreamApi.getNumber(), request -> assertMethodAndArguments(request, NeovimTabpageApi.GET_NUMBER, tabpage) ); }