我正在学习springboot，并且正在使用springwebflux和被动mongodb。我的控制器工作正常，但我的测试在空指针异常上失败。
我的身材是：

plugins {
    id 'org.springframework.boot' version '2.4.2'
    id 'io.spring.dependency-management' version '1.0.11.RELEASE'
    id 'java'
}
group = 'guru.springframework'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '11'
repositories {
    mavenCentral()
}
dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-data-mongodb-reactive'
    implementation 'org.springframework.boot:spring-boot-starter-webflux'
    implementation 'junit:junit:4.12'
    compileOnly 'org.projectlombok:lombok:1.18.16'
    annotationProcessor 'org.projectlombok:lombok:1.18.16'
    testCompileOnly 'org.projectlombok:lombok:1.18.16'
    testAnnotationProcessor 'org.projectlombok:lombok:1.18.16'
    //testCompile group: 'de.flapdoodle.embed', name: 'de.flapdoodle.embed.mongo', version: '3.0.0'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
    testImplementation 'io.projectreactor:reactor-test'
}
test {
    useJUnitPlatform()
}

我的控制器是：
包guru.springframework.spring5webfluxrest.controllers；

import guru.springframework.spring5webfluxrest.domain.Category;
import guru.springframework.spring5webfluxrest.repositories.CategoryRepository;
import org.reactivestreams.Publisher;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.*;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import java.util.concurrent.Flow;
@RestController
public class CategoryController {
    private final CategoryRepository categoryRepository;
    public CategoryController(CategoryRepository categoryRepository) {
        this.categoryRepository = categoryRepository;
    }
    @GetMapping("/api/v1/categories")
    public Flux<Category> list(){
        return categoryRepository.findAll();
    }
    @GetMapping("/api/v1/categories/{id}")
    public Mono<Category> getById(@PathVariable String id){
        return categoryRepository.findById(id);
    }
    @ResponseStatus(HttpStatus.CREATED)
    @PostMapping("/api/v1/categories")
    public Mono<Void> create(@RequestBody Publisher<Category> categoryStream){
        return categoryRepository.saveAll(categoryStream).then();
    }
    @PutMapping("/api/v1/categories/{id}")
    public Mono<Category> update (@PathVariable String id, @RequestBody Category category){
        category.setId(id);
        return categoryRepository.save(category);
    }
    @PatchMapping("/api/v1/categories/{id}")
    public Mono<Category> patch(@PathVariable String id, @RequestBody Category category){
        Category foundCategory = categoryRepository.findById(id).block();
        if(category.getDescription() != foundCategory.getDescription()){
            foundCategory.setDescription(category.getDescription());
            return categoryRepository.save(foundCategory);
        }
        return Mono.just(foundCategory);
    }
}

我的测试是：

package guru.springframework.spring5webfluxrest.controllers;
import guru.springframework.spring5webfluxrest.domain.Category;
import guru.springframework.spring5webfluxrest.repositories.CategoryRepository;
import org.junit.Before;
import org.junit.Test;
//import org.junit.jupiter.api.Test;
import org.mockito.BDDMockito;
import org.mockito.Mockito;
import org.reactivestreams.Publisher;
import org.springframework.test.web.reactive.server.WebTestClient;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.ArgumentMatchers.anyString;
import static org.mockito.BDDMockito.given;
import static org.mockito.Mockito.never;
import static org.mockito.Mockito.verify;
public class CategoryControllerTest {
    WebTestClient webTestClient;
    CategoryRepository categoryRepository;
    CategoryController categoryController;
    @Before
    public void setUp() throws Exception {
        categoryRepository = Mockito.mock(CategoryRepository.class);
        categoryController = new CategoryController(categoryRepository);
        webTestClient = WebTestClient.bindToController(categoryController).build();
    }
    @Test
    public void list() {
        given(categoryRepository.findAll())
                .willReturn(Flux.just(Category.builder().description("Cat1").build(),
                        Category.builder().description("Cat2").build()));
        webTestClient.get()
                .uri("/api/v1/categories/")
                .exchange()
                .expectBodyList(Category.class)
                .hasSize(2);
    }
    @Test
    public void getById() {
        given(categoryRepository.findById("someid"))
                .willReturn(Mono.just(Category.builder().description("Cat").build()));
        webTestClient.get()
                .uri("/api/v1/categories/someid")
                .exchange()
                .expectBody(Category.class);
    }
    @Test
    public void create() {
        given(categoryRepository.saveAll(any(Publisher.class)))
                .willReturn(Flux.just(Category.builder().description("descrp").build()));
        Mono<Category> catToSaveMono = Mono.just(Category.builder().description("Some Cat").build());
        webTestClient.post()
                .uri("/api/v1/categories")
                .body(catToSaveMono, Category.class)
                .exchange()
                .expectStatus()
                .isCreated();
    }
    @Test
    public void update() {
        given(categoryRepository.save(any(Category.class)))
                .willReturn(Mono.just(Category.builder().build()));
        Mono<Category> catToUpdateMono = Mono.just(Category.builder().description("Some Cat").build());
        webTestClient.put()
                .uri("/api/v1/categories/asdfjkl")
                .body(catToUpdateMono, Category.class)
                .exchange()
                .expectStatus()
                .isOk();
    }
    @Test
    public void testPatchNoChanges() {
        given(categoryRepository.findById(anyString()))
                .willReturn(Mono.just(Category.builder().build()));
        given(categoryRepository.save(any(Category.class)))
                .willReturn(Mono.just(Category.builder().build()));
        Mono<Category> catToUpdateMono = Mono.just(Category.builder().build());
        webTestClient.patch()
                .uri("/api/v1/categories/asdfasdf")
                .body(catToUpdateMono, Category.class)
                .exchange()
                .expectStatus()
                .isOk();
        verify(categoryRepository, never()).save(any());
    }
}

任何帮助都将不胜感激。