Added an option to deduplicate bindings in favor of Spring

User can set Environment property spring.guice.dedup=true.

src/test/java/org/springframework/guice/AdhocTestSuite.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2012-2015 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.guice;
+
+import org.junit.Ignore;
+import org.junit.runner.RunWith;
+import org.junit.runners.Suite;
+import org.junit.runners.Suite.SuiteClasses;
+
+import org.springframework.guice.annotation.EnableGuiceModulesTests;
+
+/**
+ * A test suite for probing weird ordering problems in the tests.
+ *
+ * @author Dave Syer
+ */
+@RunWith(Suite.class)
+@SuiteClasses({ BindingDeduplicationTests.class, EnableGuiceModulesTests.class })
+@Ignore
+public class AdhocTestSuite {
+
+}

src/test/java/org/springframework/guice/BindingDeduplicationTests.java

@@ -0,0 +1,66 @@
+package org.springframework.guice;
+
+import com.google.inject.AbstractModule;
+import com.google.inject.CreationException;
+import com.google.inject.Module;
+
+import org.junit.AfterClass;
+import org.junit.Test;
+
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.guice.BindingDeduplicationTests.SomeDependency;
+import org.springframework.guice.annotation.EnableGuiceModules;
+
+import static org.junit.Assert.assertNotNull;
+
+public class BindingDeduplicationTests {
+
+	@AfterClass
+	public static void cleanUp() {
+		System.clearProperty("spring.guice.dedup");
+	}
+
+	@Test
+	public void verifyNoDuplicateBindingErrorWhenDedupeEnabled() {
+		System.setProperty("spring.guice.dedup", "true");
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(
+				BindingDeduplicationTestsConfig.class);
+		SomeDependency someDependency = context.getBean(SomeDependency.class);
+		assertNotNull(someDependency);
+		context.close();
+	}
+
+	@Test(expected = CreationException.class)
+	public void verifyDuplicateBindingErrorWhenDedupeNotEnabled() {
+		System.setProperty("spring.guice.dedup", "false");
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(
+				BindingDeduplicationTestsConfig.class);
+		context.close();
+	}
+
+	public static class SomeDependency {
+	}
+
+}
+
+@EnableGuiceModules
+@Configuration
+class BindingDeduplicationTestsConfig {
+
+	@Bean
+	public SomeDependency stringBean() {
+		return new SomeDependency();
+	}
+
+	@Bean
+	public Module module() {
+		return new AbstractModule() {
+			@Override
+			protected void configure() {
+				bind(SomeDependency.class).asEagerSingleton();
+			}
+		};
+	}
+}

src/test/java/org/springframework/guice/ElementVisitorTests.java

@@ -1,23 +1,9 @@
 package org.springframework.guice;
 
-import static org.junit.Assert.assertEquals;
-
 import java.util.List;
 
 import javax.inject.Inject;
 
-import org.junit.AfterClass;
-import org.junit.BeforeClass;
-import org.junit.Test;
-import org.springframework.context.annotation.AnnotationConfigApplicationContext;
-import org.springframework.context.annotation.Bean;
-import org.springframework.context.annotation.Configuration;
-import org.springframework.guice.ElementVisitorTests.DuplicateBean;
-import org.springframework.guice.ElementVisitorTests.ElementVisitorTestGuiceBean;
-import org.springframework.guice.ElementVisitorTests.ElementVisitorTestSpringBean;
-import org.springframework.guice.annotation.EnableGuiceModules;
-import org.springframework.guice.annotation.InjectorFactory;
-
 import com.google.inject.AbstractModule;
 import com.google.inject.Guice;
 import com.google.inject.Injector;
@@ -26,48 +12,68 @@ import com.google.inject.Stage;
 import com.google.inject.spi.Element;
 import com.google.inject.spi.Elements;
 
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.guice.ElementVisitorTests.DuplicateBean;
+import org.springframework.guice.ElementVisitorTests.ElementVisitorTestGuiceBean;
+import org.springframework.guice.ElementVisitorTests.ElementVisitorTestSpringBean;
+import org.springframework.guice.annotation.EnableGuiceModules;
+import org.springframework.guice.annotation.InjectorFactory;
+
+import static org.junit.Assert.assertEquals;
+
 public class ElementVisitorTests {
 
 	private static AnnotationConfigApplicationContext context;
-	
+
 	@BeforeClass
 	public static void init() {
+		System.setProperty("spring.guice.dedup", "true");
 		context = new AnnotationConfigApplicationContext(ElementVisitorTestConfig.class);
 	}
-	
+
 	@AfterClass
 	public static void cleanup() {
-		if(context != null) {
+		System.clearProperty("spring.guice.dedup");
+		if (context != null) {
 			context.close();
 		}
 	}
 
 	@Test
 	public void verifySpringModuleDoesNotBreakWhenUsingElementVisitors() {
-		ElementVisitorTestSpringBean testSpringBean = context.getBean(ElementVisitorTestSpringBean.class);
+		ElementVisitorTestSpringBean testSpringBean = context
+				.getBean(ElementVisitorTestSpringBean.class);
 		assertEquals("spring created", testSpringBean.toString());
-		ElementVisitorTestGuiceBean testGuiceBean = context.getBean(ElementVisitorTestGuiceBean.class);
+		ElementVisitorTestGuiceBean testGuiceBean = context
+				.getBean(ElementVisitorTestGuiceBean.class);
 		assertEquals("spring created", testGuiceBean.toString());
 	}
 
-
 	public static class ElementVisitorTestSpringBean {
 		@Override
 		public String toString() {
 			return "default";
 		}
 	}
-	
+
 	public static class ElementVisitorTestGuiceBean {
 		@Inject
 		ElementVisitorTestSpringBean springBean;
+
 		@Override
 		public String toString() {
 			return springBean.toString();
 		}
 	}
 
-	public static class DuplicateBean {}
+	public static class DuplicateBean {
+	}
 }
 
 @EnableGuiceModules
@@ -76,14 +82,14 @@ class ElementVisitorTestConfig {
 
 	@Bean
 	public ElementVisitorTestSpringBean testBean() {
-		return new ElementVisitorTestSpringBean(){
+		return new ElementVisitorTestSpringBean() {
 			@Override
 			public String toString() {
 				return "spring created";
 			}
 		};
 	}
-	
+
 	@Bean
 	public Module module() {
 		return new AbstractModule() {
@@ -94,23 +100,24 @@ class ElementVisitorTestConfig {
 			}
 		};
 	}
-	
+
 	@Bean
 	public InjectorFactory injectorFactory() {
-		return new InjectorFactory() {	
+		return new InjectorFactory() {
 			@Override
 			public Injector createInjector(List<Module> modules) {
 				List<Element> elements = Elements.getElements(Stage.TOOL, modules);
-				return Guice.createInjector(Stage.PRODUCTION,Elements.getModule(elements));
+				return Guice.createInjector(Stage.PRODUCTION,
+						Elements.getModule(elements));
 			}
 		};
 	}
-	
+
 	@Bean
 	public DuplicateBean dupeBean1() {
 		return new DuplicateBean();
 	}
-	
+
 	@Bean
 	public DuplicateBean dupeBean2() {
 		return new DuplicateBean();