Versions (SpringBoot is not involved):
Spring: 5.2.16
web-app / servlet API: 4.0
JUnit: 5.8
Spring MVC Testing is not working for controller endpoint that returns ResponseEntity<ReturnStatus>, where ReturnStatus is a POJO with appropriate getters/setters. The exception triggered indicates that JSON conversion is not working for ReturnStatus. My research indicates that the annotation-based Java configuration for the WebApplicationContext is not loaded (and therefore the Jackson JSON converter is not recognized). Curiously, in a non-testing deployment in Tomcat, the controller endpoint works fine, presumably because the web.xml in the war-file is parsed by Tomcat.
QUESTION:
How can I adjust the setup for Spring MVC Test for this application so that the annotation-based Java configuration for the WebApplicationContext is properly loaded? Can this, for example, be done explicitly in the endpoint-test logic (ie, the JUnit test)?
Exception:
14:33:57,765 WARN DefaultHandlerExceptionResolver:199 - Resolved [org.springframework.http.converter.HttpMessageNotWritableException: No converter for [class com.acme.myapp.io.ReturnStatus] with preset Content-Type 'null']
14:33:57,765 DEBUG TestDispatcherServlet:1131 - Completed 500 INTERNAL_SERVER_ERROR
The Spring MVC app incorporates the following configurations:
test-context.xml, which houses Spring bean-configuration for access to data store:web.xml, which declares and maps the DispatcherServlet with relevant setup for WebApplicationContext.WebMvcConfigurer.Relevant excerpt from test-context.xml:
<context:component-scan base-package="com.acme.myapp"/>
<jpa:repositories base-package="com.acme.myapp.repos"/>
<context:property-placeholder location="classpath:/application.properties" />
<!-- Data persistence configuration -->
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>
<tx:annotation-driven transaction-manager="transactionManager" />
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
<property name="showSql" value="${db.showSql}" />
<property name="databasePlatform" value="${db.dialect}" />
<property name="generateDdl" value="${db.generateDdl}" />
</bean>
</property>
<property name="packagesToScan">
<list>
<value>com.acme.myapp.dao</value>
</list>
</property>
</bean>
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
<property name="driverClassName" value="${db.driver}" />
<property name="url" value="${db.url}" />
<property name="username" value="${db.user}" />
<property name="password" value="${db.pass}" />
<property name="initialSize" value="2" />
<property name="maxActive" value="5" />
<property name="accessToUnderlyingConnectionAllowed" value="true"/>
</bean>
<!-- Set JVM system properties here. We do this principally for hibernate logging. -->
<bean class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
<property name="targetObject">
<bean class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
<property name="targetClass" value="java.lang.System" />
<property name="targetMethod" value="getProperties" />
</bean>
</property>
<property name="targetMethod" value="putAll" />
<property name="arguments">
<util:properties>
<prop key="org.jboss.logging.provider">slf4j</prop>
</util:properties>
</property>
</bean>
Relevant excerpt from web.xml (where application-context.xml is our production version of test-context.xml):
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:application-context.xml</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<servlet>
<servlet-name>central-dispatcher</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
<init-param>
<param-name>contextClass</param-name>
<param-value>org.springframework.web.context.support.AnnotationConfigWebApplicationContext</param-value>
</init-param>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>com.acme.myapp.MyAppWebAppConfig</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>central-dispatcher</servlet-name>
<url-pattern>/api/*</url-pattern>
</servlet-mapping>
Excerpt from Java implementation of WebMvcConfigurer (ie, where we incorporate Jackson JSON converter):
@EnableWebMvc
@Configuration
@ComponentScan(basePackages = { "com.acme.myapp.controllers" })
public class MyAppWebAppConfig implements WebMvcConfigurer
{
private static final Logger logger = LoggerFactory.getLogger(MyAppWebAppConfig.class);
@Override
public void extendMessageConverters(List<HttpMessageConverter<?>> converters)
{
logger.debug("extendMessageConverters ...");
converters.add(new StringHttpMessageConverter());
converters.add(new MappingJackson2HttpMessageConverter(new MyAppObjectMapper()));
}
}
The controller endpoint looks like this (where the root is at /patients):
@RequestMapping(value = "/{id}", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity<ReturnStatus> readPatient(
@PathVariable("id") long id
)
{
ReturnStatus returnStatus = new ReturnStatus();
returnStatus.setVersionId("1.0");
...
return new ResponseEntity<ReturnStatus>(returnStatus, httpStatus);
}
Using JUnit5 and MockMvc, the endpoint-test looks like this:
@SpringJUnitWebConfig(locations={"classpath:test-context.xml"})
public class PatientControllerTest
{
private MockMvc mockMvc;
@BeforeEach
public void setup(WebApplicationContext wac) {
this.mockMvc = webAppContextSetup(wac).build();
}
@Test
@DisplayName("Read Patient from /patients API.")
public void testReadPatient()
{
try {
mockMvc.perform(get("/patients/1").accept(MediaType.APPLICATION_JSON_VALUE))
.andDo(print())
.andExpect(status().isOk());
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
Thanks!
Here are some options, possibly not exhaustive:
<mvc:annotation-driven> directive in test-context.xml. For example: <bean id="myappObjectMapper" class="com.acme.myapp.MyAppObjectMapper"/>
<mvc:annotation-driven>
<mvc:message-converters register-defaults="true">
<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<constructor-arg ref="myappObjectMapper"/>
</bean>
</mvc:message-converters>
</mvc:annotation-driven>
Effectively, this directive obviates the need for loading MyAppWebAppConfig, as <mvc:annotation-driven> in fact is the XML-equivalent of the annotation @EnableWebMvc in Java.
WebApplicationInitializer so that effectively does in Java what we configure into web.xml. For example:public class MyAppWebApplicationInitializer implements WebApplicationInitializer
{
@Override
public void onStartup(ServletContext container)
{
XmlWebApplicationContext appCtx = new XmlWebApplicationContext();
appCtx.setConfigLocation("classpath:application-context.xml");
container.addListener(new ContextLoaderListener(appCtx));
AnnotationConfigWebApplicationContext dispatcherCtx = new AnnotationConfigWebApplicationContext();
dispatcherCtx.register(MyAppWebAppConfig.class);
ServletRegistration.Dynamic registration = container.addServlet("central-dispatcher", new DispatcherServlet(dispatcherCtx));
registration.setLoadOnStartup(1);
registration.addMapping("/api/*");
}
}
For this solution, we expunge web.xml from the project; possibly we should parameterize the reference to application-context.xml as well.
Note that when I run JUnit5 tests, it appears that Spring does not instance MyAppWebApplicationInitializer, and that instead, the Spring context loaded for JUnit5 is the one referenced by the @SpringJUnitWebConfig annotation. I therefore recommend co-locating test-related configuration with test-context.xml, and reserving WebApplicationInitializer for production.
I'm sure there are other options, but I've only explored these two approaches.