问在未授权的异常情况下对onErrorResume进行Spring junit测试

EN

public Mono<String> fetch(String body, HttpHeaders headers, String correlationId) {
    Mono<String> response;
    try {
        response = postRequest(URI, headers, body);
    } catch (Exception exception) {
        throw new ExceptionHandler(HttpStatus.BAD_REQUEST, ErrorCode.REQUEST_ERROR);
    }
    return response;
}

private Mono<String> postRequest(String uri, HttpHeaders headers, String body) {
    return getStringMono(uri, headers, body).onErrorResume(exception -> {
        if (exception instanceof WebClientResponseException.Unauthorized) {
            accessTokenCache.invalidate(ACCESS_TOKEN);
            String updatedToken = accessTokenCache.getIfPresent(ACCESS_TOKEN);
            headers.replace(AUTHORIZATION, Collections.singletonList(updatedToken));
            return getStringMono(uri, headers, body);
        } else {
            log.info(exception.getMessage());
            throw new ExceptionHandler(HttpStatus.BAD_REQUEST, ErrorCode.REQUEST_ERROR);
        }
    });
}

private Mono<String> getStringMono(String uri, HttpHeaders headers, String body) {
    return webClient.post().uri(uri).headers(httpHeaders -> httpHeaders.addAll(headers))
            .body(Mono.just(body), String.class).retrieve().bodyToMono(String.class);
}

@Test
    public void testUnauthorizedException() {
        RequestBodyUriSpec reqBodyUriMock = mock(WebClient.RequestBodyUriSpec.class);
        RequestBodySpec reqBodyMock = mock(WebClient.RequestBodySpec.class);
        RequestHeadersSpec reqHeaderMock = mock(WebClient.RequestHeadersSpec.class);
        ResponseSpec responseSpec = mock(WebClient.ResponseSpec.class);
        when(webClient.post()).thenReturn(reqBodyUriMock);
        when(reqBodyUriMock.uri(ArgumentMatchers.<String>notNull())).thenReturn(reqBodyMock);
        when(reqBodyMock.headers(any())).thenReturn(requestBodySpec);
        when(reqBodyMock.body(any(), eq(String.class))).thenReturn(reqHeaderMock);
        when(reqHeaderMock.retrieve()).thenReturn(responseSpec);


        ExchangeFunction exchangeFunction = mock(ExchangeFunction.class);
        given(exchangeFunction.exchange(any(ClientRequest.class))).willReturn(Mono.error(WebClientResponseException.Unauthorized.create(HttpStatus.UNAUTHORIZED.value(), "Unauthorized", null, null, null)));

        when(responseSpec.bodyToMono(ArgumentMatchers.<Class<String>>notNull()))
                .thenThrow(WebClientResponseException.Unauthorized.create(HttpStatus.UNAUTHORIZED.value(), "Unauthorized", null, null, null));

        ExceptionHandler exception = assertThrows(
                ExceptionHandler.class, () -> client.fetch(body, headers, correlationId));
        assertEquals(ErrorCode.REQUEST_ERROR, exception.getMessage());
    }