Add test for initializers when child context created

spring-boot/src/test/java/org/springframework/boot/builder/SpringApplicationBuilderTests.java

@@ -179,6 +179,14 @@ public class SpringApplicationBuilderTests {
 		assertEquals(7, application.application().getInitializers().size());
 	}
 
+	@Test
+	public void initializersCreatedOnceForChild() throws Exception {
+		SpringApplicationBuilder application = new SpringApplicationBuilder(
+				ExampleConfig.class).child(ChildConfig.class).web(false);
+		this.context = application.run();
+		assertEquals(8, application.application().getInitializers().size());
+	}
+
 	@Test
 	public void initializersIncludeDefaults() throws Exception {
 		SpringApplicationBuilder application = new SpringApplicationBuilder(