disable the fallback to the system locale to fix unit test and establish the desired behaviour

webgoat-container/src/main/java/org/owasp/webgoat/MvcConfiguration.java

@@ -43,9 +43,11 @@ import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.io.ResourceLoader;
 import org.springframework.web.servlet.LocaleResolver;
+import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
 import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
 import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
 import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
+import org.springframework.web.servlet.i18n.LocaleChangeInterceptor;
 import org.springframework.web.servlet.i18n.SessionLocaleResolver;
 import org.thymeleaf.extras.springsecurity4.dialect.SpringSecurityDialect;
 import org.thymeleaf.spring4.SpringTemplateEngine;
@@ -53,6 +55,7 @@ import org.thymeleaf.spring4.templateresolver.SpringResourceTemplateResolver;
 import org.thymeleaf.templateresolver.TemplateResolver;
 
 import java.io.File;
+import java.util.Locale;
 
 /**
  * Configuration for Spring MVC
@@ -145,18 +148,32 @@ public class MvcConfiguration extends WebMvcConfigurerAdapter {
         Messages messages = new Messages(language);
         messages.setDefaultEncoding("UTF-8");
         messages.setBasename("classpath:i18n/messages");
+        messages.setFallbackToSystemLocale(false);
         return messages;
     }
 
     @Bean
     public LocaleResolver localeResolver() {
         SessionLocaleResolver slr = new SessionLocaleResolver();
+        slr.setDefaultLocale(Locale.ENGLISH);
         return slr;
     }
+    
+    @Bean
+    public LocaleChangeInterceptor localeChangeInterceptor() {
+        LocaleChangeInterceptor lci = new LocaleChangeInterceptor();
+        lci.setParamName("lang");
+        return lci;
+    }
 
     @Bean
     public LabelDebugger labelDebugger() {
         return new LabelDebugger();
     }
 
+    @Override
+    public void addInterceptors(InterceptorRegistry registry) {
+        registry.addInterceptor(localeChangeInterceptor());
+    }
+    
 }