Test thymeleaf processing

I'd like to create some tests that assert that thymeleaf templates will render given some context. I found I can do the following example, and it will yield the same result I get as when I call a web route.

@ExtendWith(SpringExtension.class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT, classes={WebApp.class,  H2JpaConfig.class})
@ActiveProfiles("test")
public class Foo {

    @Autowired
    SpringTemplateEngine templateEngine;

    @Test
    void letsTestThymeleaf(){

        var context = new Context();

        // add some variables

        assertDoesNotThrow(() -> templateEngine.process("templateDirectory/some-template", context));
    }
}

Now, this is a rather expensive thing as it starts the whole application, including database and webserver. Can I strip this down to just whatever the SpringTemplateEngine needs to do its job?