Change exception message for missing Thymeleaf templates

Fixes gh-424

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/thymeleaf/ThymeleafAutoConfiguration.java

@@ -84,8 +84,11 @@ public class ThymeleafAutoConfiguration {
 			if (checkTemplateLocation) {
 				Resource resource = this.resourceLoader.getResource(this.environment
 						.getProperty("prefix", DEFAULT_PREFIX));
-				Assert.state(resource.exists(), "Cannot find template location: "
-						+ resource + " (are you really using Thymeleaf?)");
+				Assert.state(
+						resource.exists(),
+						"Cannot find template location: "
+								+ resource
+								+ " (please add some templates or check your Thymeleaf configuration)");
 			}
 		}
 

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/thymeleaf/ThymeleafAutoConfigurationTests.java

@@ -16,11 +16,11 @@
 
 package org.springframework.boot.autoconfigure.thymeleaf;
 
+import java.io.File;
 import java.util.Collections;
 import java.util.Locale;
 
 import org.junit.After;
-import org.junit.Ignore;
 import org.junit.Test;
 import org.springframework.beans.factory.BeanCreationException;
 import org.springframework.boot.autoconfigure.PropertyPlaceholderAutoConfiguration;
@@ -95,8 +95,8 @@ public class ThymeleafAutoConfigurationTests {
 	}
 
 	@Test
-	@Ignore("Fix this for gh-424")
 	public void templateLocationEmpty() throws Exception {
+		new File("target/test-classes/templates/empty-directory").mkdir();
 		EnvironmentTestUtils.addEnvironment(this.context,
 				"spring.thymeleaf.prefix:classpath:/templates/empty-directory/");
 		this.context.register(ThymeleafAutoConfiguration.class,