Align TransactionManagementConfigurer support in TCF with production

This commit picks up where 613bd3be1d
left off by ensuring that a transaction manager configured via the
TransactionManagementConfigurer API takes precedence over any
transaction manager configured as a bean in the ApplicationContext
unless @Transactional is configured with a qualifier for the explicit
transaction manager to use in tests.

Closes gh-24869

spring-test/src/main/java/org/springframework/test/context/transaction/TestContextTransactionUtils.java

@@ -183,13 +183,6 @@ public abstract class TestContextTransactionUtils {
 			if (bf instanceof ListableBeanFactory) {
 				ListableBeanFactory lbf = (ListableBeanFactory) bf;
 
-				// Look up single bean by type
-				Map<String, PlatformTransactionManager> txMgrs =
-						BeanFactoryUtils.beansOfTypeIncludingAncestors(lbf, PlatformTransactionManager.class);
-				if (txMgrs.size() == 1) {
-					return txMgrs.values().iterator().next();
-				}
-
 				// Look up single TransactionManagementConfigurer
 				Map<String, TransactionManagementConfigurer> configurers =
 						BeanFactoryUtils.beansOfTypeIncludingAncestors(lbf, TransactionManagementConfigurer.class);
@@ -203,6 +196,13 @@ public abstract class TestContextTransactionUtils {
 					return (PlatformTransactionManager) tm;
 				}
 
+				// Look up single bean by type
+				Map<String, PlatformTransactionManager> txMgrs =
+						BeanFactoryUtils.beansOfTypeIncludingAncestors(lbf, PlatformTransactionManager.class);
+				if (txMgrs.size() == 1) {
+					return txMgrs.values().iterator().next();
+				}
+
 				try {
 					// Look up single bean by type, with support for 'primary' beans
 					return bf.getBean(PlatformTransactionManager.class);

spring-test/src/test/java/org/springframework/test/context/transaction/manager/LookUpTxMgrViaTransactionManagementConfigurerWithSingleTxMgrBeanTests.java

@@ -0,0 +1,99 @@
+/*
+ * Copyright 2002-2020 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
+ *
+ *      https://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.test.context.transaction.manager;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
+import org.springframework.test.context.transaction.AfterTransaction;
+import org.springframework.transaction.TransactionManager;
+import org.springframework.transaction.annotation.TransactionManagementConfigurer;
+import org.springframework.transaction.annotation.Transactional;
+import org.springframework.transaction.testfixture.CallCountingTransactionManager;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Integration test that verifies the behavior for transaction manager lookups
+ * when only one transaction manager is configured as a bean in the application
+ * context and a non-bean transaction manager is configured via the
+ * {@link TransactionManagementConfigurer} API.
+ *
+ * @author Sam Brannen
+ * @since 5.3
+ */
+@SpringJUnitConfig
+@Transactional
+class LookUpTxMgrViaTransactionManagementConfigurerWithSingleTxMgrBeanTests {
+
+	@Autowired
+	CallCountingTransactionManager txManager;
+
+	@Autowired
+	Config config;
+
+
+	@Test
+	void transactionalTest() {
+		assertThat(txManager.begun).isEqualTo(0);
+		assertThat(txManager.inflight).isEqualTo(0);
+		assertThat(txManager.commits).isEqualTo(0);
+		assertThat(txManager.rollbacks).isEqualTo(0);
+
+		CallCountingTransactionManager annotationDriven = config.annotationDriven;
+		assertThat(annotationDriven.begun).isEqualTo(1);
+		assertThat(annotationDriven.inflight).isEqualTo(1);
+		assertThat(annotationDriven.commits).isEqualTo(0);
+		assertThat(annotationDriven.rollbacks).isEqualTo(0);
+	}
+
+	@AfterTransaction
+	void afterTransaction() {
+		assertThat(txManager.begun).isEqualTo(0);
+		assertThat(txManager.inflight).isEqualTo(0);
+		assertThat(txManager.commits).isEqualTo(0);
+		assertThat(txManager.rollbacks).isEqualTo(0);
+
+		CallCountingTransactionManager annotationDriven = config.annotationDriven;
+		assertThat(annotationDriven.begun).isEqualTo(1);
+		assertThat(annotationDriven.inflight).isEqualTo(0);
+		assertThat(annotationDriven.commits).isEqualTo(0);
+		assertThat(annotationDriven.rollbacks).isEqualTo(1);
+	}
+
+
+	@Configuration
+	static class Config implements TransactionManagementConfigurer {
+
+		final CallCountingTransactionManager annotationDriven = new CallCountingTransactionManager();
+
+		@Bean
+		TransactionManager txManager() {
+			return new CallCountingTransactionManager();
+		}
+
+		@Override
+		public TransactionManager annotationDrivenTransactionManager() {
+			return annotationDriven;
+		}
+
+	}
+
+}

spring-tx/src/test/java/org/springframework/transaction/annotation/EnableTransactionManagementTests.java

@@ -168,6 +168,29 @@ public class EnableTransactionManagementTests {
 		ctx.close();
 	}
 
+	@Test
+	public void txManagerIsResolvedCorrectlyWithSingleTxManagerBeanAndTxMgmtConfigurer() {
+		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(
+				EnableTxConfig.class, SingleTxManagerBeanAndTxMgmtConfigurerConfig.class);
+		assertThat(ctx.getBeansOfType(TransactionManager.class)).hasSize(1);
+		TransactionalTestBean bean = ctx.getBean(TransactionalTestBean.class);
+		CallCountingTransactionManager txManager = ctx.getBean(CallCountingTransactionManager.class);
+		SingleTxManagerBeanAndTxMgmtConfigurerConfig config = ctx.getBean(SingleTxManagerBeanAndTxMgmtConfigurerConfig.class);
+		CallCountingTransactionManager annotationDriven = config.annotationDriven;
+
+		// invoke a transactional method, causing the PlatformTransactionManager bean to be resolved.
+		bean.findAllFoos();
+
+		assertThat(txManager.begun).isEqualTo(0);
+		assertThat(txManager.commits).isEqualTo(0);
+		assertThat(txManager.rollbacks).isEqualTo(0);
+		assertThat(annotationDriven.begun).isEqualTo(1);
+		assertThat(annotationDriven.commits).isEqualTo(1);
+		assertThat(annotationDriven.rollbacks).isEqualTo(0);
+
+		ctx.close();
+	}
+
 	/**
 	 * A cheap test just to prove that in ASPECTJ mode, the AnnotationTransactionAspect does indeed
 	 * get loaded -- or in this case, attempted to be loaded at which point the test fails.
@@ -384,6 +407,30 @@ public class EnableTransactionManagementTests {
 	}
 
 
+	@Configuration
+	static class SingleTxManagerBeanAndTxMgmtConfigurerConfig implements TransactionManagementConfigurer {
+
+		final CallCountingTransactionManager annotationDriven = new CallCountingTransactionManager();
+
+		@Bean
+		public TransactionalTestBean testBean() {
+			return new TransactionalTestBean();
+		}
+
+		@Bean
+		public PlatformTransactionManager txManager() {
+			return new CallCountingTransactionManager();
+		}
+
+		// The transaction manager returned from this method is intentionally not
+		// registered as a bean in the ApplicationContext.
+		@Override
+		public PlatformTransactionManager annotationDrivenTransactionManager() {
+			return annotationDriven;
+		}
+	}
+
+
 	@Configuration
 	@EnableTransactionManagement
 	static class Spr11915Config {