Allow @Import to be used directly on test classes

Remove the need for a nested @Configuration class when writing a test
that need to @Import configuration.

Primarily added to allow @ImportAutoConfiguration to be used directly
on test classes.

Fixes gh-5473

spring-boot-test/src/test/java/org/springframework/boot/test/context/ImportsContextCustomizerFactoryIntegrationTests.java

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2012-2016 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.boot.test.context;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import org.springframework.beans.factory.NoSuchBeanDefinitionException;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.ImportsContextCustomizerFactoryIntegrationTests.ImportedBean;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.annotation.Import;
+import org.springframework.stereotype.Component;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Integration tests for {@link ImportsContextCustomizerFactory} and
+ * {@link ImportsContextCustomizer}.
+ *
+ * @author Phillip Webb
+ */
+@RunWith(SpringRunner.class)
+@Import(ImportedBean.class)
+public class ImportsContextCustomizerFactoryIntegrationTests {
+
+	@Autowired
+	private ApplicationContext context;
+
+	@Autowired
+	private ImportedBean bean;
+
+	@Test
+	public void beanWasImported() throws Exception {
+		assertThat(this.bean).isNotNull();
+	}
+
+	@Test(expected = NoSuchBeanDefinitionException.class)
+	public void testItselfIsNotABean() throws Exception {
+		this.context.getBean(getClass());
+	}
+
+	@Component
+	static class ImportedBean {
+
+	}
+
+}

spring-boot-test/src/test/java/org/springframework/boot/test/context/ImportsContextCustomizerFactoryTests.java

@@ -0,0 +1,156 @@
+/*
+ * Copyright 2012-2016 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.boot.test.context;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Import;
+import org.springframework.stereotype.Component;
+import org.springframework.test.context.ContextCustomizer;
+import org.springframework.test.context.MergedContextConfiguration;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests for {@link ImportsContextCustomizerFactory} and {@link ImportsContextCustomizer}.
+ *
+ * @author Phillip Webb
+ */
+public class ImportsContextCustomizerFactoryTests {
+
+	@Rule
+	public ExpectedException thrown = ExpectedException.none();
+
+	private ImportsContextCustomizerFactory factory = new ImportsContextCustomizerFactory();
+
+	@Test
+	public void getContextCustomizerWhenHasNoImportAnnotationShouldReturnNull() {
+		ContextCustomizer customizer = this.factory
+				.createContextCustomizer(TestWithNoImport.class, null);
+		assertThat(customizer).isNull();
+	}
+
+	@Test
+	public void getContextCustomizerWhenHasImportAnnotationShouldReturnCustomizer() {
+		ContextCustomizer customizer = this.factory
+				.createContextCustomizer(TestWithImport.class, null);
+		assertThat(customizer).isNotNull();
+	}
+
+	@Test
+	public void getContextCustomizerWhenHasMetaImportAnnotationShouldReturnCustomizer() {
+		ContextCustomizer customizer = this.factory
+				.createContextCustomizer(TestWithMetaImport.class, null);
+		assertThat(customizer).isNotNull();
+	}
+
+	@Test
+	public void contextCustomizerEqualsAndHashCode() throws Exception {
+		ContextCustomizer customizer1 = this.factory
+				.createContextCustomizer(TestWithImport.class, null);
+		ContextCustomizer customizer2 = this.factory
+				.createContextCustomizer(TestWithImport.class, null);
+		ContextCustomizer customizer3 = this.factory
+				.createContextCustomizer(TestWithImportAndMetaImport.class, null);
+		ContextCustomizer customizer4 = this.factory
+				.createContextCustomizer(TestWithSameImportAndMetaImport.class, null);
+		assertThat(customizer1.hashCode()).isEqualTo(customizer1.hashCode());
+		assertThat(customizer1.hashCode()).isEqualTo(customizer2.hashCode());
+		assertThat(customizer1).isEqualTo(customizer1).isEqualTo(customizer2)
+				.isNotEqualTo(customizer3);
+		assertThat(customizer3).isEqualTo(customizer4);
+	}
+
+	@Test
+	public void getContextCustomizerWhenClassHasBeanMethodsShouldThrowException()
+			throws Exception {
+		this.thrown.expect(IllegalStateException.class);
+		this.thrown.expectMessage("Test classes cannot include @Bean methods");
+		this.factory.createContextCustomizer(TestWithImportAndBeanMethod.class, null);
+	}
+
+	@Test
+	public void contextCustomizerImportsBeans() throws Exception {
+		ContextCustomizer customizer = this.factory
+				.createContextCustomizer(TestWithImport.class, null);
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
+		customizer.customizeContext(context, mock(MergedContextConfiguration.class));
+		context.refresh();
+		assertThat(context.getBean(ImportedBean.class)).isNotNull();
+	}
+
+	static class TestWithNoImport {
+
+	}
+
+	@Import(ImportedBean.class)
+	static class TestWithImport {
+
+	}
+
+	@MetaImport
+	static class TestWithMetaImport {
+
+	}
+
+	@MetaImport
+	@Import(AnotherImportedBean.class)
+	static class TestWithImportAndMetaImport {
+
+	}
+
+	@MetaImport
+	@Import(AnotherImportedBean.class)
+	static class TestWithSameImportAndMetaImport {
+
+	}
+
+	@Import(ImportedBean.class)
+	static class TestWithImportAndBeanMethod {
+
+		@Bean
+		public String bean() {
+			return "bean";
+		}
+
+	}
+
+	@Retention(RetentionPolicy.RUNTIME)
+	@Import(ImportedBean.class)
+	@interface MetaImport {
+
+	}
+
+	@Component
+	static class ImportedBean {
+
+	}
+
+	@Component
+	static class AnotherImportedBean {
+
+	}
+
+}