Freemarker and Spring in JUnit tests

Question

As in many Java apps, we're using Freemarker in our app to render emails. We've found that some of our templates weren't rendering exactly as we thought they would, and so we realized that we ought to write some unit tests for our template rendering. Well I set up the tests, and immediately received a FileNotFoundException: Template "my/template.ftl" not found.

I figured that this must be both a solved problem with an easy solution. That was many work hours ago, and I realized that I was wrong; from what I can tell, this is neither solved nor easy!

Our app's setup is, I think, pretty standard. We have a Maven project, and store our Freemarker templates in src/main/webapp/WEB-INF/freemarker. Although most of our app's functionality is initiated by Quartz jobs, we deploy it as a webapp. Therefore the following configuration in our spring XML file is all that we need:

<bean id="freemarkerConfiguration"
    class="org.springframework.ui.freemarker.FreeMarkerConfigurationFactoryBean">
    <property name="templateLoaderPath" value="/WEB-INF/freemarker/" />
</bean>

Then in our code, we Autowire the bean in like so:

@Autowired
protected Configuration freemarkerConfiguration;

and use it like so:

Template template = freemarkerConfiguration.getTemplate("mail/job/detail.ftl");

That works great in the context of our deployed app, executing within a Quartz job. But we always get the template not found when running from within unit tests.

I tried many different approaches, none of which worked. The last involved creating my own Freemarker TemplateLoader implementation, and trying to get it to load the Freemarker template files form the classpath. The problems with that approach are that a) the same classloading code that I successfully use elsewhere in tests would not find the template, b) I'm not sure all that is involved with correctly implementing a TemplateLoader, and c) this all just seems overly-complicated in general.

I may continue this route, but first... am I missing something obvious? One of Freemarker's benefits is that it doesn't require an HTTP context, so why would it be so difficult to use Freemarker outside of a web app context?

Answer 1

Dave,

ftl files being used from location src/main/webapp/... are not in classpath. And i beleive your testing class is on location src/test/... which will not have visibility into the ftl files (which are actually in src/main/webapp//WEB-INF/freemarker/mail/job/*.ftl) and so you get template not found exception. If you want them to be on classpath, put the files in src/test/resources.

Answer 2

I've found that using the MockMvc allows my unit tests to find the ftl templates in src/main/resources [target/classes]. But when I use the TestRestTemplate, it only sees the ftl templates in src/test/resources [target/test-classes].

In my case I'm using @SpringBootTest. Im not sure if that is relevant.

Also, you can see better debug output if you turn up the level on these namespaces.

logging.level.freemarker=TRACE
logging.level.org.springframework.ui.freemarker=DEBUG
logging.level.org.springframework.web.servlet.view.freemarker=DEBUG