Verify that TestContextBootstrapper resolution ignores duplicates

This commit introduces a test to verify that multiple declarations of
@BootstrapWith that register the same TestContextBootstrapper type
(i.e., duplicates) do not result in an error.

Issue: SPR-17006

spring-test/src/test/java/org/springframework/test/context/BootstrapUtilsTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -27,7 +27,6 @@ import org.springframework.test.context.support.DefaultTestContextBootstrapper;
 import org.springframework.test.context.web.WebAppConfiguration;
 import org.springframework.test.context.web.WebTestContextBootstrapper;
 
-import static org.hamcrest.CoreMatchers.containsString;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.mockito.Mockito.mock;
@@ -47,6 +46,29 @@ public class BootstrapUtilsTests {
 	@Rule
 	public final ExpectedException exception = ExpectedException.none();
 
+	@Test
+	public void resolveTestContextBootstrapperWithEmptyBootstrapWithAnnotation() {
+		BootstrapContext bootstrapContext = BootstrapTestUtils.buildBootstrapContext(EmptyBootstrapWithAnnotationClass.class, delegate);
+		
+		exception.expect(IllegalStateException.class);
+		exception.expectMessage("Specify @BootstrapWith's 'value' attribute");
+		
+		resolveTestContextBootstrapper(bootstrapContext);
+	}
+	
+	@Test
+	public void resolveTestContextBootstrapperWithDoubleMetaBootstrapWithAnnotations() {
+		BootstrapContext bootstrapContext = BootstrapTestUtils.buildBootstrapContext(
+			DoubleMetaAnnotatedBootstrapWithAnnotationClass.class, delegate);
+
+		exception.expect(IllegalStateException.class);
+		exception.expectMessage("Configuration error: found multiple declarations of @BootstrapWith");
+		exception.expectMessage(FooBootstrapper.class.getName());
+		exception.expectMessage(BarBootstrapper.class.getName());
+
+		resolveTestContextBootstrapper(bootstrapContext);
+	}
+
 	@Test
 	public void resolveTestContextBootstrapperForNonAnnotatedClass() {
 		assertBootstrapper(NonAnnotatedClass.class, DefaultTestContextBootstrapper.class);
@@ -57,16 +79,6 @@ public class BootstrapUtilsTests {
 		assertBootstrapper(WebAppConfigurationAnnotatedClass.class, WebTestContextBootstrapper.class);
 	}
 
-	@Test
-	public void resolveTestContextBootstrapperWithEmptyBootstrapWithAnnotation() {
-		BootstrapContext bootstrapContext = BootstrapTestUtils.buildBootstrapContext(EmptyBootstrapWithAnnotationClass.class, delegate);
-
-		exception.expect(IllegalStateException.class);
-		exception.expectMessage(containsString("Specify @BootstrapWith's 'value' attribute"));
-
-		resolveTestContextBootstrapper(bootstrapContext);
-	}
-
 	@Test
 	public void resolveTestContextBootstrapperWithDirectBootstrapWithAnnotation() {
 		assertBootstrapper(DirectBootstrapWithAnnotationClass.class, FooBootstrapper.class);
@@ -83,18 +95,10 @@ public class BootstrapUtilsTests {
 	}
 
 	@Test
-	public void resolveTestContextBootstrapperWithDoubleMetaBootstrapWithAnnotation() {
-		BootstrapContext bootstrapContext = BootstrapTestUtils.buildBootstrapContext(
-			DoubleMetaAnnotatedBootstrapWithAnnotationClass.class, delegate);
-
-		exception.expect(IllegalStateException.class);
-		exception.expectMessage(containsString("found multiple declarations of @BootstrapWith"));
-		exception.expectMessage(containsString(FooBootstrapper.class.getName()));
-		exception.expectMessage(containsString(BarBootstrapper.class.getName()));
-
-		resolveTestContextBootstrapper(bootstrapContext);
+	public void resolveTestContextBootstrapperWithDuplicatingMetaBootstrapWithAnnotations() {
+		assertBootstrapper(DuplicateMetaAnnotatedBootstrapWithAnnotationClass.class, FooBootstrapper.class);
 	}
-
+	
 	private void assertBootstrapper(Class<?> testClass, Class<?> expectedBootstrapper) {
 		BootstrapContext bootstrapContext = BootstrapTestUtils.buildBootstrapContext(testClass, delegate);
 		TestContextBootstrapper bootstrapper = resolveTestContextBootstrapper(bootstrapContext);
@@ -112,14 +116,24 @@ public class BootstrapUtilsTests {
 	@Retention(RetentionPolicy.RUNTIME)
 	static @interface BootWithFoo {}
 
+	@BootstrapWith(FooBootstrapper.class)
+	@Retention(RetentionPolicy.RUNTIME)
+	static @interface BootWithFooAgain {}
+
 	@BootstrapWith(BarBootstrapper.class)
 	@Retention(RetentionPolicy.RUNTIME)
 	static @interface BootWithBar {}
 
-	static class NonAnnotatedClass {}
-
+	// Invalid
 	@BootstrapWith
 	static class EmptyBootstrapWithAnnotationClass {}
+	
+	// Invalid
+	@BootWithBar
+	@BootWithFoo
+	static class DoubleMetaAnnotatedBootstrapWithAnnotationClass {}
+	
+	static class NonAnnotatedClass {}
 
 	@BootstrapWith(FooBootstrapper.class)
 	static class DirectBootstrapWithAnnotationClass {}
@@ -129,10 +143,10 @@ public class BootstrapUtilsTests {
 	@BootWithBar
 	static class MetaAnnotatedBootstrapWithAnnotationClass {}
 
-	@BootWithBar
 	@BootWithFoo
-	static class DoubleMetaAnnotatedBootstrapWithAnnotationClass {}
-
+	@BootWithFooAgain
+	static class DuplicateMetaAnnotatedBootstrapWithAnnotationClass {}
+	
 	@WebAppConfiguration
 	static class WebAppConfigurationAnnotatedClass {}