Support automatic discovery of default TELs

Prior to this commit, there was no declarative mechanism for a custom
TestExecutionListener to be registered as a default
TestExecutionListener.

This commit introduces support for discovering default
TestExecutionListener implementations via the SpringFactoriesLoader
mechanism. Specifically, the spring-test module declares all core
default TestExecutionListeners under the
org.springframework.test.context.TestExecutionListener key in its
META-INF/spring.factories properties file, and third-party frameworks
and developers can contribute to the list of default
TestExecutionListeners in the same manner.

 - AbstractTestContextBootstrapper uses the SpringFactoriesLoader to
   look up the class names of all registered default
   TestExecutionListeners and sorts the instantiated listeners using
   AnnotationAwareOrderComparator.

 - DefaultTestContextBootstrapper and WebTestContextBootstrapper now
   rely on the SpringFactoriesLoader mechanism for finding default
   TestExecutionListeners instead of hard coding fully qualified class
   names.

 - To ensure that default TestExecutionListeners are registered in the
   correct order, each can implement Ordered or declare @Order.

 - AbstractTestExecutionListener and all default TestExecutionListeners
   provided by Spring now implement Ordered with appropriate values.

 - Introduced "copy constructors" in MergedContextConfiguration and
   WebMergedContextConfiguration

 - SpringFactoriesLoader now uses AnnotationAwareOrderComparator
   instead of OrderComparator.

Issue: SPR-11466

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

@@ -45,7 +45,7 @@ public class TestExecutionListenersTests {
 	@Test
 	public void verifyNumDefaultListenersRegistered() throws Exception {
 		TestContextManager testContextManager = new TestContextManager(DefaultListenersExampleTestCase.class);
-		assertEquals("Num registered TELs for DefaultListenersExampleTestCase.", 4,
+		assertEquals("Num registered TELs for DefaultListenersExampleTestCase.", 5,
 			testContextManager.getTestExecutionListeners().size());
 	}
 

spring-test/src/test/java/org/springframework/test/context/jdbc/TransactionalSqlScriptsTests.java

@@ -16,12 +16,19 @@
 
 package org.springframework.test.context.jdbc;
 
+import javax.sql.DataSource;
+
 import org.junit.FixMethodOrder;
 import org.junit.Test;
+import org.junit.runner.RunWith;
 import org.junit.runners.MethodSorters;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.test.annotation.DirtiesContext;
 import org.springframework.test.context.ContextConfiguration;
-import org.springframework.test.context.junit4.AbstractTransactionalJUnit4SpringContextTests;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.test.jdbc.JdbcTestUtils;
+import org.springframework.transaction.annotation.Transactional;
 
 import static org.junit.Assert.*;
 
@@ -31,11 +38,21 @@ import static org.junit.Assert.*;
  * @author Sam Brannen
  * @since 4.1
  */
+@RunWith(SpringJUnit4ClassRunner.class)
 @FixMethodOrder(MethodSorters.NAME_ASCENDING)
 @ContextConfiguration(classes = EmptyDatabaseConfig.class)
+@Transactional
 @Sql({ "schema.sql", "data.sql" })
 @DirtiesContext
-public class TransactionalSqlScriptsTests extends AbstractTransactionalJUnit4SpringContextTests {
+public class TransactionalSqlScriptsTests {
+
+	protected JdbcTemplate jdbcTemplate;
+
+
+	@Autowired
+	public void setDataSource(DataSource dataSource) {
+		this.jdbcTemplate = new JdbcTemplate(dataSource);
+	}
 
 	@Test
 	// test##_ prefix is required for @FixMethodOrder.
@@ -50,6 +67,10 @@ public class TransactionalSqlScriptsTests extends AbstractTransactionalJUnit4Spr
 		assertNumUsers(2);
 	}
 
+	protected int countRowsInTable(String tableName) {
+		return JdbcTestUtils.countRowsInTable(this.jdbcTemplate, tableName);
+	}
+
 	protected void assertNumUsers(int expected) {
 		assertEquals("Number of rows in the 'user' table.", expected, countRowsInTable("user"));
 	}