Add FeatureMethodErrorTests

Capture common mistakes with @feature method declarations and ensure
that useful error messages are produced.

Author: cbeams

org.springframework.context/src/main/java/org/springframework/context/annotation/ConfigurationClassPostProcessor.java

@@ -322,7 +322,8 @@ private void processFeatureMethod(final Method featureMethod, Object configInsta
 			if (!(FeatureSpecification.class.isAssignableFrom(featureMethod.getReturnType()))) {
 				// TODO SPR-7420: raise a Problem instead?
 				throw new IllegalArgumentException(
-						"return type from @Feature methods must be assignable to FeatureSpecification");
+						format("Return type for @Feature method %s.%s() must be assignable to FeatureSpecification",
+								featureMethod.getDeclaringClass().getSimpleName(), featureMethod.getName()));
 			}
 
 			List<Object> beanArgs = new ArrayList<Object>();

org.springframework.context/src/test/java/org/springframework/context/annotation/FeatureMethodErrorTests.java

@@ -0,0 +1,113 @@
+/*
+ * Copyright 2002-2011 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.context.annotation;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.junit.Assert.assertThat;
+import static org.junit.Assert.fail;
+
+import org.junit.Test;
+import org.springframework.context.annotation.configuration.StubSpecification;
+import org.springframework.context.config.FeatureSpecification;
+
+import test.beans.TestBean;
+
+/**
+ * Tests proving that @Feature methods may reference the product of @Bean methods.
+ *
+ * @author Chris Beams
+ * @since 3.1
+ */
+public class FeatureMethodErrorTests {
+
+	@Test
+	public void incorrectReturnType() {
+		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
+		ctx.register(FeatureConfig.class);
+		try {
+			ctx.refresh();
+			fail("expected exception");
+		} catch (FeatureMethodExecutionException ex) {
+			assertThat(ex.getCause().getMessage(),
+					equalTo("Return type for @Feature method FeatureConfig.f() must be " +
+							"assignable to FeatureSpecification"));
+		}
+	}
+
+	@Test
+	public void voidReturnType() {
+		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
+		ctx.register(VoidFeatureConfig.class);
+		try {
+			ctx.refresh();
+			fail("expected exception");
+		} catch (FeatureMethodExecutionException ex) {
+			assertThat(ex.getCause().getMessage(),
+					equalTo("Return type for @Feature method VoidFeatureConfig.f() must be " +
+							"assignable to FeatureSpecification"));
+		}
+	}
+
+	@Test
+	public void containsBeanMethod() {
+		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
+		ctx.register(FeatureConfigWithBeanMethod.class);
+		try {
+			ctx.refresh();
+			fail("expected exception");
+		} catch (FeatureMethodExecutionException ex) {
+			assertThat(ex.getMessage(),
+					equalTo("@FeatureConfiguration classes must not contain @Bean-annotated methods. " +
+							"FeatureConfigWithBeanMethod.testBean() is annotated with @Bean and must " +
+							"be removed in order to proceed. Consider moving this method into a dedicated " +
+							"@Configuration class and injecting the bean as a parameter into any @Feature " +
+							"method(s) that need it."));
+		}
+	}
+
+
+	@FeatureConfiguration
+	static class FeatureConfig {
+		@Feature
+		public Object f() {
+			return new StubSpecification();
+		}
+	}
+
+
+	@FeatureConfiguration
+	static class VoidFeatureConfig {
+		@Feature
+		public void f() {
+		}
+	}
+
+
+	@FeatureConfiguration
+	static class FeatureConfigWithBeanMethod {
+		@Feature
+		public FeatureSpecification f() {
+			return new StubSpecification();
+		}
+
+		@Bean
+		public TestBean testBean() {
+			return new TestBean();
+		}
+	}
+
+}

org.springframework.integration-tests/src/test/java/org/springframework/context/annotation/FeatureTestSuite.java

@@ -16,27 +16,39 @@
 
 package org.springframework.context.annotation;
 
-
 /**
  * Tests directly or indirectly related to {@link FeatureConfiguration} class and
  * {@link Feature} method processing.
  *
  * @author Chris Beams
  * @since 3.1
- */
-/*
+ * 
  * commented due to classpath visibility differences between Eclipse
  * and Ant/Ivy at the command line.  Eclipse can see classes across
  * project test folders, Ant/Ivy are not configured to do so. Uncomment
  * as necessary when doing @Feature-related work.
- * 
+import org.junit.runner.RunWith;
+import org.junit.runners.Suite;
+import org.junit.runners.Suite.SuiteClasses;
+import org.springframework.transaction.TxNamespaceHandlerTests;
+import org.springframework.transaction.annotation.AnnotationTransactionNamespaceHandlerTests;
+import org.springframework.transaction.annotation.TxAnnotationDrivenFeatureTests;
+import org.springframework.transaction.config.AnnotationDrivenTests;
+import org.springframework.web.servlet.config.AnnotationDrivenBeanDefinitionParserTests;
+import org.springframework.web.servlet.config.MvcAnnotationDrivenFeatureTests;
+import org.springframework.web.servlet.config.MvcDefaultServletHandlerTests;
+import org.springframework.web.servlet.config.MvcNamespaceTests;
+import org.springframework.web.servlet.config.MvcResourcesTests;
+import org.springframework.web.servlet.config.MvcViewControllersTests;
+
 @RunWith(Suite.class)
 @SuiteClasses({
 	EarlyBeanReferenceProxyCreatorTests.class,
 	SimpleFeatureMethodProcessingTests.class,
 	BeanFactoryAwareFeatureConfigurationTests.class,
 	FeatureMethodBeanReferenceTests.class,
 	FeatureMethodQualifiedBeanReferenceTests.class,
+	FeatureMethodErrorTests.class,
 	FeatureConfigurationClassTests.class,
 	FeatureMethodEarlyBeanProxyTests.class,
 	FeatureConfigurationImportTests.class,
@@ -60,9 +72,8 @@
 	MvcViewControllersTests.class,
 	MvcResourcesTests.class,
 	MvcDefaultServletHandlerTests.class,
-	MvcNamespaceTests.class,
-})
- */
+	MvcNamespaceTests.class
+*/
 public class FeatureTestSuite {
 
 }